Well it looks a whole heck of a lot like a cisco rollover, so I can understand why you'd get that wrong. And using both at the same time just adds to the confusion! :)
That would be the only blue cisco that _wasn't_ a rollover. I have hundreds of them, spanning decades, and ALL of the blue ones are rollover. The very rare black ones are straight - I have a few, but have no clue what box they're hiding in. (the blue one are everywhere. :-)) In theory, I have one of the _very_ new ones with the usb converter built in. (very nice.)
Telephone technician here. Something I noticed when the modem went to dial at one point, I heard static coming over the modem speaker. You have a loose connection on one of your phone lines that's causing static. That would explain the junk data you're seeing on the terminal. Try swapping your rj11 patch cords, and check the pins on the rj11 jacks on the modems and the linksys ATA. See if you have any green corrosion on any of the pins in the RJ11 ports.
It seems odd to be able to recognize the difference but the dial-up connection at 30:15 has some static. I'm not sure what side is talking at that moment but maybe this helps. Also the connection sounds at 26:30, might have some static too, but you talked over a little bit and cut it off once it sounded close. Maybe in the original clip you can hear the static a little better.
Yup, I suspected the phone line connections as well from hearing the static over the speaker. Back in the day, we used to have fun dialing up our friends computer and then picked up the phone and spoke into the phone while it was in use by the modem connection. The resulting garbage on the screen was very similar. It may not be a voice, but it is a sign of static interference in the phone line itself. Definitely test your cables and check those connections.
Friendly neighborhood graybeard network engineer here. I’ve actually used modems connected to the console of a terminal server connected to the consoles of routers to fix misbehaving routers internationally. That SD/RD flashing you were seeing is most likely the router and modem in an error message feedback loop. I’ll see if I can find the magic init string and Cisco serial settings (we had the inbound modem on console, and used aux for dialing out from the router) we used to make it all work. I do know that we used sportsters, so whatever documentation I find should be directly applicable to your setup.
It makes sense that echo is causing it to get wrapped up in a loop, the Cisco would be sending out a config command etc and getting it straight back as an echo, which would mean sending an error out and getting it back and on and on again
Or a local echo enabled at the modem while Cisco expects ATE0. Setting software flow control will make it go away but it's only a band-aid not a cure, if I'm right.
When I was younger in the late 2000s, I war dialed a bunch of numbers. One day I found an open Cisco router. Someone either forgot to log out or didn't add an aux password. The router's config was secured from editing but I could run commands to view its configuration, routing protocols, and interfaces. It was pretty cool.
Try this for an init string on your modems: AT&F&C1&D2S0=1 AT means attention, &F recalls factory defaults, &C1 enables data carrier detect, &D2 does something that I can't remember, and S0=1 turns on auto answer. I used to run BBSes back in the day and this is a generic modem initialization string that we used to use. Edit: AT&V Will display the modems factory defaults and if you change things you can use AT&W to write them to the modem's NVRAM and then you can recall them with a simple ATZ command. 🙂
This channel represents all that’s well with “The Internet” + our technician here works with all the same junk I’ve been dealing with from 2000 to 2007 😅 Amazing Sun / compaq / USR / Cisco memories - thanks a lot !! Please continue making videos !!
fun bit of knowledge about those AT commands. Modern cellular modems for data only usually have the same old AT commands for configuration and troubleshooting. Not bad for a 40 year old command set 😁
In fact when the original ESP8266 chips first came out and were marketed solely as WiFi add-ons for Arduinos-before people realized they could just use them directly and cut the Arduino out entirely-they also only used AT commands over serial for communication (presumably an updated command set that included commands for setting WiFi network name and password)
You need to put the modem connected to the router into "quiet mode" so that it doesn't send the result codes to the router. What's probably happening is the router is sending *something* to the modem, and the modem is returning "ERROR". The router doesn't know what that means, so it sends its own error message to the modem, which makes the modem return "ERROR" again, which makes this feedback loop of data over the serial connection. Likewise, when the line rings the modem sends "RING" which will confuse the router as well. The Sportster modems have a DIP switch on the bottom to suppress result codes. Not sure how it's done on the Ultra 96; maybe ATQ1. It's also possible that any modem whose history you don't know can have weird settings set from its previous life. It's not a bad idea to enter AT&F1 to initialize the default settings, and then AT&W to save those settings. And as someone else said, your issue at the very end of the video is a crappy phone connection :)
Thats what I'm thinking. It seems to be getting something between the terminal as soon as the serial is connected and most likely the reason why the overrun is going up.
You learn the best when you have to troubleshoot. I have no doubt you'll figure it out. And thanks again for bringing me way back to the past when I would dial my neighbour with my 14.4modem and chat using the terminal.
Oh the bad old days. I used to have to deal with OOB modems all the time. We found a config that worked and stuck to it. I don't remember enough about it anymore to be much help though. I do remember that the init strings are usually the problem....and solution. lol Thanks for the video.
All of this brings back old memories. In the 90s and 2000s I worked on a lot of cisco, and forgot the console cable so often that I had memorised the pin-out and would just cut a network cable and old serial or modem cable and twist the wires together. We also used to take two 56k modems and give them AT commands so they never dialled and put them on either end of a "analogue leased line", which was just a normal ptsn line with a fixed fee, and then run pppd over it so that people could be online 24/7 before broadband came along. In the early 2000s I plugged a nokia phone to a linux box in the data center and used mincom and shell scripts so I could send and sms with commands and it would sms back the output and it could even run bash and send me back a page of out put as a bunch of sms's broken into 250 char chunks.
Did you get 56k out of the line? My memory of it was that 56k was one-way, and the fast-sending-end had to be on a digital line. The other direction was "only" able to do 38.6 like the previous generation. They were basically capitalising on the fact that most modern modem pools of the time were digital modems on digital trunks.
@@RichardBetel Most people using them got 56k, except me cause I was 84km from the office and the rest were walking distance from the office. Ours were just duxbury 56k modems plugged to a Linux box on each side, and we ran bsd compression to get that 1 or 2 k/s extra. We didn't have our own modem racks because the telecoms company in my country had pops all over and you just leased "ports" and set up your own RADIUS and relm and they would forward authentication requests to you.
@@RachaelSA Interesting! I didn't know that regular "consumer grade" 56k modems could answer at 56k. (You can't get 56k over a digital phone network with two modems using analogue wiring, and thus I just assumed that the modems didn't support answering at 56k as that would be a rarely-if-ever used feature).
I love watching your videos. I'll never have your patience, so I enjoy very much living vicariously through you. It's traveling back in time, nostalgia overload, and extremely educating and informative. We get to follow along and learn from your frustrations and roadblocks, with none of the effort on our part 😂. Thank you so much, never stop doing these videos. I commend you, from Argentina 🇦🇷🙌🏻👏🏻
21:03 In 2022 I was doing tech support where I would have to help remote techs fix/check network hardware over dial up in places like 7-11 and other chain stores. Many times I was asked to make sure the dial up modem was plugged in and status lights were on or blinking as the network was down and dial up was the fail safe. I had a landline phone very similar to yours that I could check dial tone and verify the number connected to the modem. Many times I would arrive on site and the modem was off or unplugged from the phone line. So dialup modems are still used in the corporate IT world.
Ahh how I love your videos! I too am also a lover/collector of all things Cisco (my current collection: Cisco 1760, 2610, and a 2811 - with Call Manager, two Catalyst 3524's - one PWR, two 7920's and one 7960 SIP, and lastly the BIG DADDY a Catalyst 5505 Sup. II with a 24 port eth card.). I really enjoy watching you come up and work through random networking projects just because you enjoy the fun journey of learning and most importantly because you can and enjoy it! These are the exact reasons why I continue to collect devices and work on building a wild corporate sized network in my residential home lol. Please keep up the awesome work!
I would recommend turning off the modem's auto answer. The cisco should be able to answer on it's own. Using the modem auto-answer is really for attaching the modem to something that doesn't understand that there's a modem there such as a console port. For anything vaguely intelligent that's supposed to drive a modem, it should be listening for RING and responding to the modem with ATA to make it answer and also expect to hear that CONNECT line rather than be surprised when that shows up. Modem hardware auto answer is an archaic feature that was obsolete before the internet era.
As someone who is currently on a networking / cyber security internship while i study for my networks and cyber degree, this old stuff is fascinating. It seems amazing how straight forward everything seems now even though I'm doing CCNA v7
Great video! This is a topic that I actually know things about. Not the Cisco part but everything else. Here are my suggestions: A: Make a serial sniffer cable. Take a straight DB25 cable that you connect in series with whatever you want to sniff/debug. Add two additional cabels to that DB25 cable, that in turn connect to the input pins of two serial ports of a computer (or perhaps your 8-port terminal server). Connect those two cables in a way that each sniffs signals from each direction. The simplest use case then is to just run two Putty instances on your computer, one for each sniffer port, but the better way is to use some dedicated software that indicates all flow control signals and whatnot too, and puts all text in the same windows with for example different colors to distinguish who sends what. This is 100% the best DIY way to actually know what's going on on a RS232 connection. With this you can easily tell if for example the Cisco device and the modem are just echoing each others commands in a never ending echo ping pong loop. B: For video creation purposes, and also perhaps to trouble shoot the noise other commenters mention, you can build a simple adapter to tap the phone line. A capacitor in series, say 0.1µF rated at 200V or so in series with a voltage divider with say 47k - 4.7k, and two "antiparallell" diodes across the lower resistor ("antiparallell"= two diodes in parallell, but turned in opposite directions). You can then connect an audio cable to the resistor-diodes combo (ground/shield to the wire that goes to the phone line) and listen using a line input on anything that has NO CONNECTION TO GROUND. I.E. a cheap USB sound card on a laptop running on battery power (and to be safe no other wires connected), or for that sake a 1980's boom box or whatnot. Note that the speakers in the Sportster modems are terrible. They are more or less just a piezo buzzer that is hooked up to reproduce audio rather than just buzz. You can't distinguish correct clicks and whatnot from line noise. C: As someone else have already stated - at least the 33k6 and newer modems already have error correction built in and thus any line noise or for that sake not-terrible compression issues on the phone line / ATA side shouldn't be a problem with those modems. D: I also agree with the comment that suggest you try modem-modem connection with two computers (or two serial ports on the same computer) and make sure things are solid this way first. If you use some classic "modem" terminal emulator software you can also try sending files and check which speed you get, and any retransmissions (select ZMODEM for file transfers, it does error correction and whatnot and is generally the best choice compared to the older YMODEM, XMODEM and KERMIT in most cases). E: You can also try connecting the AUX port on the Cisco device directly to a computer, maybe with a crossover cable, maybe not. You should be able to manually "emulate" a modem by pasting RING, wait for the Cisco device to say ATA and then paste CONNECT 9600 or similar in the terminal window. Note that you have to paste the strings as the slowness of manually typing might make the Cisco device think it's noise or whatnot. (Not sure if this is the case for Cisco devices but in general modem related software/firmware works this way). F: If you give up on repairing the fully dead 33k6 modem, maybe ask Epictronic (UA-cam) if they are interested in having a look at it. After all, the USR modems are x86 based (IIRC they use the 80188) so they are fairly close to the PC's that Epictronics are already working on. G: I've written this before, and I'm writing this again: I really wish/recommend that you get a classic office use PBX. Just make sure you get one that don't mangle the audio, i.e. either one that is old enough to connect the audio using analogue paths, or one with digital audio that is actually 8 bit and 8kHz sample rate. I'm biased by my own great experiences but if you can find a cheap Ericsson ASB 150/02, also known as Businessphone 50, 150 or 250 depending on enclosure size, they are a good choice. With a newer CPU card you can also connect to it using SIP over TCP/IP, while the older ones "only" do analogue, E1/T1 and it's proprietary desk phones. The minimum viable configuration for your use would be one CPU card and one ELU-A card (for connecting analogue phones/modems) but you would most likely also want a BTU-A card (to connect to your ATAs and whatnot, especially if you don't find one with a new enough CPU card to have SIP). H: Keep up with all your great videos!
You can also use an AUX port to chain Cisco gear consoles together. You can connect the AUX from one to the CON of the other. Additionally, you can connect an AUX port to the serial port on older time servers (before they were IP-connected).
It's got to be the wire/connectors between the devices causing the issues. Try a different set of wires/adapters. If a new in box 56k modem is presenting the same issues as the other modems, it's not the modems.
One of my favorite periodic chores at work is going through and testing to make sure all our out of band management works, spending most of a day just dialing into terminal servers (Hayes commands and all) even calling the numbers to listen for line noise or intercept recordings.
I had that same modem and it died with all the lights coming on, I was more of a internal modem guy and the battle of the standard for 56k was between us robotics with X-2 and motorola with K56 was fun too. Had dual modems in the server with two phone lines and you could pool the modems together, that's the best u got back then before broadband but luckily we had ISDN in my neighborhood thanks to my neighbors company and he hooked us up with a 128k ISDN connection. The modem pooling was cool just like remote access with it here, miss the sounds probly the most and still remember all the AT commands lol. Great vid man and good work as always.
Ah modems. My childhood. I kinda miss the sounds they produced. I used to put a pillow over it to muffle the sound when i was calling bulletin boards at night so i didn't wake my parents 😅
We had a backdoor modem line at the ISP I worked for in the 90's, I believe it was attached to a Livingston Portmaster, from it we could telnet (pre-ssh!) to servers to fix things.
Those problems with the modem scream degraded capacitors to me. Any piece of equipment like that which takes low-voltage AC in will have a small bridge rectifier on the input directly after the connector. This then rectifies to 9 * 1.414 =12.7VDC. The capacitors directly after the bridge rectifier have to be good quality to provide a nice, stable DC supply that, critically, can provide large current spikes when needed - for example when trying to switch a relay. If this capacitor, or the bypass cap on the 5V regulator, have gone bad then the digital electronics could be seeing a large amount of ripple on their power rails which causes all sorts of crazy havoc with CMOS circuitry. If you've got even a cheap oscilloscope (even one of the really, really basic things like the Arduino-scope would be acceptable as all you're concerned about is under 500Hz) and you probe the voltage rails while it's on, that will instantly tell you what's wrong. Additionally, if you replace the caps, you can safely just connect a 12VDC adapter to the modem with no issues, assuming it's laid out as I described.
I just realized something else -- the issue could also be inadequate or intermittent ground. When you noticed the power supply cable was damaged, did you do a full continuity check? Or check to see if the lines were shorted together at all? That could also be causing some of your issues, and would explain why the data lights are blinking randomly -- the current for the circuit is returning via the grounds on the serial port instead of through the power connector. However, it still could be bad capacitors. I would definitely try using a different power adapter if you have one handy just to eliminate that as a potential cause. Oh, and I forgot to explain at the end of my original comment *why* you'd want to switch to a DC supply. First, they're cheaper and easier to find, especially in 9V/12V versions. Second, the input stage doesn't have to deal with the AC ripple after rectification, which means the main supply capacitors have an easier time overall. And third, typically a good quality DC power brick will have more protection than the cheapo AC wall warts, which are usually literally just a small transformer with a fuse... DC supplies often have over/undervoltage protection, overcurrent protection, overtemperature, etc...
Oh, I should have waited till the end of the video to comment. Yeah, I have a feeling most of the issues are coming from flow control. Just turn flow control off entirely on both ends.
Back in the late 90’s - mid 00’s my office had Frame Relay with modem backup to RAS server. Worked pretty well and kept us connected. We weren’t web surfing over that connection strictly database stuff.
You can piggyback from an AUX on Router A to a Console on Router B, SSH/Telnet to Router A, and then dial into Router B. We used them more for that than anything back in the day.
Two things. Do a factory reset on the modems so you have a known starting point. Second, repin your DB-25 so you can use a standard Ethernet cable. Cisco used to sell an six cable but it was part of an expensive kit. 3rd party companies made the cables for $20 each. I used to build these configs for remote access into a data center. It kept me from having to drive in 100 miles at 2am when a router or switch crashed. It’s been a long time since I thought about doing this stuff. I had a stack of the nice Hayes 2400 baud modems in those nice extruded aluminum cases. Good memories /cough
My Dad used to work for a big bank and would bring these home when they were “retired”. My friend and I had a Cisco 2500 at each of our houses and used to play LAN games over dialup.
Believe it or not, my infrastructure at work actually has a couple of routers set up with dial-in access via 56K modems today. We have no admin access to these routers so our ISP manages them for us and utilize the dial-in function only as backup if they can't log in via the T-1 WAN interface (yes, we also still have T-1 links). We had to get standard analog POTS lines run for each router, assisted in setting up the modems, etc... this was a few years ago but yeah, we still utilize this technology today.
Very nice, I'm glad people seem to be getting back into modems these days. I've got plans to set up a dial up ISP that you can access over a VoIP ATA if you should so desire.
Never thought about using an ATA in that manner, port to port locally, definitely going to try that. Thx. I swear I remember there being a rack mount for the Hayes SmartModems, think you had to take the modem apart to mount them in it. Held 3 modems in a rack U.
You have truly fascinating gear. Stuff I always wondered how it worked. Such as dial up networking. Your various server stuff is really cool. I can never afford to mess around with ancient gear, so this is the next best thing. Well, that, and I don’t have the room. Ok, ok. I hate clutter.
You are causing me to remember some serious late nights sat in data centres in the nineties trying to get this stuff working. One thing that caused me enough issues i still remember it, check your your RJ45->DB25 converter connects *both* the middle ground pins on the RJ45 to pin 7 on the DB25 some did not and some DTE only used one pin on the RJ45 which caused all manner of insanity with signals which looks remarkably like your strange behaviour.
My knee-jerk is to say turn off all flow control while testing. It really only matters when you're doing high-throughput and there's a chance of a buffer overrun. He won't see that when typing commands at a console prompt. Also, as I recall, the high-speed modems (anything faster than 9600) worked best when the serial ports were fixed at a speed that was faster than their best connection speed... It's been nearly 30 years since I used a modem. We switched to ISDN BRI asafp. I feel old.
13:55 I remember my USR 14.4 modem having some built in help for the AT commands, I think the command for it was AT$. It would print a bunch of text explaining what most of the AT commands do. Also ATS$ would tell you what all the S-registers did.
For a "Networking" class I took for my CS degree I wanted more of a challenge, so I used an Arduino with a temperature sensor that would log the data to a PHP script and a database, but the Arduino was connected to a GMRS modem/module and I stumbled though sending AT commands to send a GET request with the data in the URL of my PHP site. I had no clue why those commands worked but I presented first to the class with the most complex project and didn't have to do anything the rest of the week.
In both datacenters at my previous employer, they used USRobotics Courier modems in the AUX port of the Cisco Routers. They are long and slim. Those modems are supposed to be the best of the best and survive poor line conditions, etc. Might be worth a shot. Can’t ever have too many modems. 🤷🏻♂️
24:43 it looks like the paper became moist at some point in time in the past and dried up again, causing it to stick. You could reverse this probably by steaming the whole package, i.e. bring water to a boil and then place the whole package on a sieve above the water so the steam can penetrate it. Once it's soaked again you should be able to carefully pull the pages apart and then let them dry spread out.
Nice! I have 2 broken ATA adapters, and cannot configure them, but one of them still has the 48v on the RJ11 although it will not give the dialtone, but the voltage is all that you need. You dont have to degrade the connection passing it through voip filters, in this way, it connects the best speed the modem has at optimal conditions. All that you need is a RJ11 phone line splitter, that beige adapter that has a male and 2 females RJ11, so you plug the adapter into one of the MUTE ATA ports (you don´t want the dialtone, because it will mess the connection, disable the service) just to get the voltage and the 2 phone cables in back of the adapter, so the modems will listen eachother. The 2 modems must be on the same ATA port! If you dont havean adapter, just mend together 3 RJ11 cable ends, plug one on each device! Now you need to pass some AT commands, ATX0DT123 on the modem dialing, X0 disables the dial tone detection, so it dials right away, without complaining No Dialtone and on the other modem the command ATA to answer the call. I Still Have my precious USR Courier from the old times! I think it will never connect 56k X2 or v.90 because the telco did some trickery for it to work, but it will connect v.34, the com port speed must be configured 115.200bps. You can try using some Terminal program, I use the classic Procomm Plus! It also supports telnet BBS´s that are still around. I have it installed in a Win98 oracle virtualbox, machine and it can access the COM1 port on the host to use the modem.
Former telco ISP architect here. RS232 is such a pain. We had a main Sun server (back before redundancy was a thing) that ran everything but authentication. If you accidentally knocked the DB25 out, the server would shut down. Fun times.
The Teal 33,600 and "Sportster 33.6 Faxmodem" is such a vibe, a moment in time like '95? '96? I had this exact unit and moving up from a Hayes 9600 felt like a monumental change, I was holding the future in my hands. I don't quite recall what the deal was with their Sportster branding, but it felt like it was meant to be portable, because it was so sleek and stylin.
I had the same problem with my fax through the SPA, I had to change the "Preferred Codec" (G711U) and "FAX CED Detect Enable" (YES) this fixed so much, but if you can hear a noise on the line then you might need to clean a cable or keep it away from SMPS
One other thing. If you’re in to hacking modems, you will enjoy poking Wi-Fi access points at the hardware level. They use the AT command set as well. They have a few extra commands but same idea.
For everyone thinking AT-commands are arcane, quite a few 5G modems are still controlled by AT-commands. The command set has been extended multiple times, but still, it's based on the same old Hayes AT command set.
Never trust a premade cable or adapter! Troubleshooting serial connections almost always requires a simple breakout box that goes between the DB25 socket and plug. It's nothing more than a bunch of LEDs and possibly jumper cables to reconfigure the connection. To connect a DTE (Data Terminal Equipment, the router) to a DCE (Data Communications Equipment, a modem), you need to connect GND, Rx, Tx, RTS, CTS, DSR, DTR, CD and RI all straight through (that's one more than an RJ45 plug can provide; at least one signal must be missing from the router). CD (Carrier Detect) is important because it tells the DTE that the connection is finally established. RI (Ring Indicator) allows the DTE to answer calls whithout resorting to the auto answer setting of the modem. RTS and CTS were originally meant to turn on the transmitter hardware (Request To Send) and signal back its state (Clear To Send). They're typically used for hardware handshake in later implementations like smart modems. DSR and DTR are more or less static signals to indicate that the devices are turned on and ready. Smart modems are special because they can autodetect the baud rate of the serial interface by monitioring the receive line for the "AT" command. The speed between the modem and the DTE is independent from the connection speed over the telephone line. Some modems even add data compression to the latter. This makes handshaking between the DTE and the modem absolutely neccessary. It's always a good idea to set the DTE baud rate to a higher value then the actual connection speed. As others have already pointed aout, in order to troubleshoot the runaway Rx/Tx blinking you should check for local echo settings on each side of the connection. This may create a tight feedback loop, just like a microphone close to a speaker. You can debug this by feeding one of the data lines to an additional serial interface and use a terminal application to monitor the data. Maybe you should hunt for an actual line monitor which might come handy in other cases, too.
Honestly, I believe the advent of the remote access “feature” was what sparked the rivalry between network engineers and security engineers. As an old-school (late 90s) security engineer, I can’t help but love, but also at the same time hate, just a little bit, this video.
i enjoy Clabretro and at 5:36 those Cisco IP phones I have seen those in schools but those phones could dial an outside line with 9 to reach an outside line and then a phone number and mostly those phones could call internally other phones in schools offices and classrooms
Some notes - BUSY is generated by the phone network in analog settings. If you hear a busy signal on an analog line, the network (ATA in this case) is giving that signal. A black screen after CONNECT usually indicates a flow control or cabling issue. Easiest thing to try is turning off all flow control. At slower speeds, you can usually get away without having it. If that doesn't work, check your cabling, most likely your adapters. There's multiple types of serial cables/adapters and they aren't all interchangeable.
I have a rack in my basement called The Lan Before Time, with some 386 and 486 machines, after seeing this and another person I got a 3825 to get dialup and token ring working.
I still have my USR Sportster Flash v92 modem from way back in 1997! Now from some vague memory to just have the AA enabled you normally need some sort of host otherwise yes you can dial in but nothing passes between the two... It's been a very long time since I have used AT comands like that!
Try dialing into the modem while it's connected to your computer (from USB modem to old modem). That way you can check the modems can connect without fail. Also fun-fact some US Robotics modems didn't need dial-tone to connect to each other -- If you issue dial command (ATDT) on one and answer command (ATA) on the other they will connect without a physical ATA unit in between.
Once ran a BBS with a Fido node. Seems an eternity ago. One thing that jumped at me was the IO errors on the router. You don't appear to have a serial buffer. Back in my day, the 16550UART was basically table stakes for modem or serial comm port. This is part of the "hardware control" in the connection. Why the router doesn't have a buffer is almost certainly because they expected the user to have that AUX connected to a device with an external buffer. Perhaps a hub of some sort for the AUX lines. Perhaps what your octopus cord plugs into. I don't know how to get around that for the router. But on your PC side, the buffer needs to be on the PC. Most PCs with a 9-pin serial port have a UART because go hand in hand. For a PC without native serial ports, we got ISA or maybe PCI cards with serial ports. They also made PCMCIA cards, I believe. I use an old Dell D630 notebook with a serial port for all my modem tinkering. It has a built in modem but I own a stack of external modems like the Courier and multiple Hayes and Practical Peripherals externals that I love using. Nothing sounds better than a V.FC connect tone sequence. Man. Anyway, back to your PC, a typical serial to USB dongle might not have a buffer, nor would any USB port. It's not something needed these days. But the router needs it, apparently. Workaround: slow down the router baud rate until the IO errors stop. I would get a really good modem like a Courier first and then try going to lower and lower baud rates until it stops having those errors. Good luck. Caveat: I am old enough to no longer remember important stuff.
The USB, USR 33k and V.92 modems have V.42, which uses LAPM or MNP to detect any noise and transmission errors, and retransmit faulty data. Usually this is enabled by default, BUT your line is either so noisy thst it falls back to unprotected, or LAPM is disabled in the permanent configuration of your modems. Try playing around with the +ES and \N commands, write the config with &W to permanent store (or check with +ES? what the setting is). During connection establishing, it should display CONNECT (speed) LAPM or V.42. Example command sequence to try: AT+ES=3,2,4 AT\N2 AT&W This forces the modem to negotiate either LAPM or MNP, and quits if error correction can't be established. You need to do this on the V92, 33k and USB modem, and on both sides. The 9600 modem can't do this. Check the documentation of your modem types if they have the values different, but the ones I gave you are pretty standard.
For once you and I seem to have some of the same equipment! I have a US Robotics 33.6K sportster just like yours from 1995, yours is in a bit better shape but it was neat to see someone else with one. Mine I got second hand from an old employer, it used to run hyperterminal for system management of a few sites.... The modem was connected to a IBM Windows XP machine and was in production until its retirement in 2017. Had the modem ever since. Once in awhile it comes out for use. At one point it even was in my tech bag and was used as a butt-set. Not ideal, but it got the job done until I could afford a proper unit. Anyway... modems. I think I've been watching your channel now for.... 2 years? 3 years? Something like that? Anyway, your comfort with the Cisco terminal has grown a lot, not that you were bad with it or something like that before, but it's obvious that it's far far less of a strange black box that you might not be comfortable with, great job! Occasionally I visit classes working with Cisco equipment and it's always neat to see the students getting more comfortable with the Cisco CLI, just something neat about seeing it, hard to explain. Anyway, keep up the good work!
Try using an ethernet cable as a phone cord, like just take 2 pairs from cat 5e or cat6 cable and terminate rj11 connectors on there, the twisted pair may eliminate some noise on the line that was heard at one point
Try turning off local echo on the modem connected to the router. The modem and router are probably getting into an error feedback loop and that’s the RD/SD activity you’re seeing. After enough of this it might cause the router to stop talking on the aux port. You’ll need to be to write your modem config so it’ll persist on power cycle.
AT commandset is also used in USB cellular modems. Disk in, change settings on it. Its crazy how some guys ridiculous Monday morning idea was built into millions of products. 😂
Look into an ADTRAN 908E, it has full internal TDM switching and supports dialup between extensions REALLYYY well. It’s managed just like a Cisco router thru the CLI or you can enable the webui which is helpful
So weird, my work had a 1921 router at a remote location I visited earlier last year and despite the ISP no longer providing dial up, it still had a cable hooked into the AUX port going into a still powered on dial up modem. Wow.
Before randomly plugging in old wall warts (power adapters) into any equipment, ESPECIALLY the old linear types, you need to check their voltage output first. If they're DC, you also need to check the ripple. Transformers used in these power adapters degrade over time from heat and vibration, as well as the pressure from the windings in the core. What eventually happens is that the enamel coating on the wire will disintegrate or move around and cause windings to start shorting out. When this happens, the output voltage will start rising, and it can get alarmingly out of spec. I found this out the hard way a few decades ago with my Sega Genesis. I went to turn it on one day and the console would run for a few minutes and then crash repeatedly. After investigating, the LM7805 regulators were smoking hot and had started desoldering themselves from the logic board. Further investigation showed that the original Sega branded wall wart that was originally 9 volts was 27.5 volts. This shocked me at the time, so I started checking all of the old linear type wall warts I had at the time, and I found that none of them that were older than 5 or 6 years were anywhere near what they were supposed to be. My oldest wall warts at the time from the late 80s and early 90s were all over 15 volts, when they should have been 9 volts or less. Some were over 20 volts, and the Sega one the 27.5 volts. After testing hundreds of wall warts over the years and doing destructive failure analysis, I've come to the conclusion that they all will fail by design. Whenever I see an old wall wart like the ones in the video, they get trashed and replaced with a modern SMPS power supply. That is unless it requires AC like the modems here, in which case I'll just buy an off the shelf transformer and make my own housing for it and trash the old unit. I would hazard a guess that the working US Robotics modem that just recently died was killed by the wall wart blasting it with voltage that's too high. The old one that just lights up everything was probably blown up by a lightning strike or other power surge, they were particularly susceptible to that.
The first modem I ever owned was a 1200. My Dad had a 2400, but I was able to score the 1200 internal ISA card for my own Blue Chip clone. Yeah, 1200 was painfully slow.
AA flashing like that is a visual indication of an incoming ring voltage. I think one of yhe S registers tells the modem to pickup on a certain number of rings. This was so you could have other equipment on thhe same line like a fax.
If that is a SPA-2102 I have a video on my channel for unlocking locked ones, FYI The nice thing about 300baud modems is you can type faster than they transmit makes you feel like a super hacker
NOTE: I call the light blue RJ45 cable I'm using a "rollover" cable, which it is not. It's a straight through cable (correct for this application).
Well it looks a whole heck of a lot like a cisco rollover, so I can understand why you'd get that wrong. And using both at the same time just adds to the confusion! :)
Yes! I knew it was straight through but that light blue got me calling it a rollover haha
@@clabretro i had good luck using a normal rj45 to db9 serial cisco console cable with a db25 to db9 adapter instead of the strate rj45 cable
That would be the only blue cisco that _wasn't_ a rollover. I have hundreds of them, spanning decades, and ALL of the blue ones are rollover. The very rare black ones are straight - I have a few, but have no clue what box they're hiding in. (the blue one are everywhere. :-)) In theory, I have one of the _very_ new ones with the usb converter built in. (very nice.)
@@jfbeam I have a yellow cisco serial cable that I think came with a Nexus.
Telephone technician here. Something I noticed when the modem went to dial at one point, I heard static coming over the modem speaker. You have a loose connection on one of your phone lines that's causing static. That would explain the junk data you're seeing on the terminal. Try swapping your rj11 patch cords, and check the pins on the rj11 jacks on the modems and the linksys ATA. See if you have any green corrosion on any of the pins in the RJ11 ports.
you beat me to this one. , but I second the replacement of the rj11 cables
I'll try that!
9v AC causing interference with that non-twisted pair?
It seems odd to be able to recognize the difference but the dial-up connection at 30:15 has some static. I'm not sure what side is talking at that moment but maybe this helps. Also the connection sounds at 26:30, might have some static too, but you talked over a little bit and cut it off once it sounded close. Maybe in the original clip you can hear the static a little better.
Yup, I suspected the phone line connections as well from hearing the static over the speaker. Back in the day, we used to have fun dialing up our friends computer and then picked up the phone and spoke into the phone while it was in use by the modem connection. The resulting garbage on the screen was very similar. It may not be a voice, but it is a sign of static interference in the phone line itself. Definitely test your cables and check those connections.
From a junior IT admin/student, your videos never cease to be an amazing source of inspiration to me! Much love from Serbia!
Same, i find it fascinating, but also horribly grueling and id never want to do it myself lol
@@renderedpixels4300very different doing it professionally vs as a hobby
Pozdrav od ovaj Srbin iz New Jersey USA 😅
Friendly neighborhood graybeard network engineer here. I’ve actually used modems connected to the console of a terminal server connected to the consoles of routers to fix misbehaving routers internationally. That SD/RD flashing you were seeing is most likely the router and modem in an error message feedback loop. I’ll see if I can find the magic init string and Cisco serial settings (we had the inbound modem on console, and used aux for dialing out from the router) we used to make it all work. I do know that we used sportsters, so whatever documentation I find should be directly applicable to your setup.
It makes sense that echo is causing it to get wrapped up in a loop, the Cisco would be sending out a config command etc and getting it straight back as an echo, which would mean sending an error out and getting it back and on and on again
@@charlesturner897 True, that would also explain why at 22:49 the modem "issued" commands meant for the modem to the Cisco gear via serial.
Or a local echo enabled at the modem while Cisco expects ATE0. Setting software flow control will make it go away but it's only a band-aid not a cure, if I'm right.
Really cool seeing your persistence in figuring things out. I haven't touched this stuff in years
thank you!
When I was younger in the late 2000s, I war dialed a bunch of numbers. One day I found an open Cisco router. Someone either forgot to log out or didn't add an aux password. The router's config was secured from editing but I could run commands to view its configuration, routing protocols, and interfaces. It was pretty cool.
“Made it this far”!?!? Who isn’t glued to your videos from pre-roll through post-roll ad? Valiant effort…you get it.
Try this for an init string on your modems: AT&F&C1&D2S0=1
AT means attention, &F recalls factory defaults, &C1 enables data carrier detect, &D2 does something that I can't remember, and S0=1 turns on auto answer. I used to run BBSes back in the day and this is a generic modem initialization string that we used to use.
Edit: AT&V Will display the modems factory defaults and if you change things you can use AT&W to write them to the modem's NVRAM and then you can recall them with a simple ATZ command. 🙂
This channel represents all that’s well with “The Internet” + our technician here works with all the same junk I’ve been dealing with from 2000 to 2007 😅 Amazing Sun / compaq / USR / Cisco memories - thanks a lot !! Please continue making videos !!
thank you!
fun bit of knowledge about those AT commands. Modern cellular modems for data only usually have the same old AT commands for configuration and troubleshooting. Not bad for a 40 year old command set 😁
Yes, but their command set is even more cryptic.
In fact when the original ESP8266 chips first came out and were marketed solely as WiFi add-ons for Arduinos-before people realized they could just use them directly and cut the Arduino out entirely-they also only used AT commands over serial for communication (presumably an updated command set that included commands for setting WiFi network name and password)
You need to put the modem connected to the router into "quiet mode" so that it doesn't send the result codes to the router. What's probably happening is the router is sending *something* to the modem, and the modem is returning "ERROR". The router doesn't know what that means, so it sends its own error message to the modem, which makes the modem return "ERROR" again, which makes this feedback loop of data over the serial connection. Likewise, when the line rings the modem sends "RING" which will confuse the router as well. The Sportster modems have a DIP switch on the bottom to suppress result codes. Not sure how it's done on the Ultra 96; maybe ATQ1.
It's also possible that any modem whose history you don't know can have weird settings set from its previous life. It's not a bad idea to enter AT&F1 to initialize the default settings, and then AT&W to save those settings.
And as someone else said, your issue at the very end of the video is a crappy phone connection :)
Thats what I'm thinking. It seems to be getting something between the terminal as soon as the serial is connected and most likely the reason why the overrun is going up.
FR = For Real! Its happening over dialup.
awwww yeaaahhh
For real? (ryuji voice)
My thought was FR is for Frame Relay. lol
You learn the best when you have to troubleshoot. I have no doubt you'll figure it out.
And thanks again for bringing me way back to the past when I would dial my neighbour with my 14.4modem and chat using the terminal.
Oh the bad old days. I used to have to deal with OOB modems all the time. We found a config that worked and stuck to it. I don't remember enough about it anymore to be much help though. I do remember that the init strings are usually the problem....and solution. lol Thanks for the video.
All of this brings back old memories. In the 90s and 2000s I worked on a lot of cisco, and forgot the console cable so often that I had memorised the pin-out and would just cut a network cable and old serial or modem cable and twist the wires together. We also used to take two 56k modems and give them AT commands so they never dialled and put them on either end of a "analogue leased line", which was just a normal ptsn line with a fixed fee, and then run pppd over it so that people could be online 24/7 before broadband came along. In the early 2000s I plugged a nokia phone to a linux box in the data center and used mincom and shell scripts so I could send and sms with commands and it would sms back the output and it could even run bash and send me back a page of out put as a bunch of sms's broken into 250 char chunks.
Did you get 56k out of the line? My memory of it was that 56k was one-way, and the fast-sending-end had to be on a digital line. The other direction was "only" able to do 38.6 like the previous generation. They were basically capitalising on the fact that most modern modem pools of the time were digital modems on digital trunks.
@@RichardBetel Most people using them got 56k, except me cause I was 84km from the office and the rest were walking distance from the office. Ours were just duxbury 56k modems plugged to a Linux box on each side, and we ran bsd compression to get that 1 or 2 k/s extra. We didn't have our own modem racks because the telecoms company in my country had pops all over and you just leased "ports" and set up your own RADIUS and relm and they would forward authentication requests to you.
@@RachaelSA Interesting! I didn't know that regular "consumer grade" 56k modems could answer at 56k.
(You can't get 56k over a digital phone network with two modems using analogue wiring, and thus I just assumed that the modems didn't support answering at 56k as that would be a rarely-if-ever used feature).
This is the most I have used my CCNA in decades 😂
Was this in CCNA or CCNP? I remember doing these in my Cisco studies around 2005-2008. Fun memories :D
I love watching your videos. I'll never have your patience, so I enjoy very much living vicariously through you. It's traveling back in time, nostalgia overload, and extremely educating and informative. We get to follow along and learn from your frustrations and roadblocks, with none of the effort on our part 😂.
Thank you so much, never stop doing these videos. I commend you, from Argentina 🇦🇷🙌🏻👏🏻
thank you!
This is super cool nostalgia - for my CCIE circa 2001 I connected aux ports back to back on 2500s to learn dialer profiles
Adds a new meaning to the phrase..... "Pass me the AUX cord bro"
I love the eloquent use of that "PBX" lol
This is just such a cool channel. Been subbed since 15k and you always end up grabbing my full attention for the entire runtime!
glad to hear that!
21:03 In 2022 I was doing tech support where I would have to help remote techs fix/check network hardware over dial up in places like 7-11 and other chain stores. Many times I was asked to make sure the dial up modem was plugged in and status lights were on or blinking as the network was down and dial up was the fail safe. I had a landline phone very similar to yours that I could check dial tone and verify the number connected to the modem. Many times I would arrive on site and the modem was off or unplugged from the phone line. So dialup modems are still used in the corporate IT world.
Clab loves tinkering it seems, is that what we love. New video arriving at my birthday is a good treat, thanks)
@5:40 FINALLY! Been waiting to see a 7900 series on the channel!
Ahh how I love your videos! I too am also a lover/collector of all things Cisco (my current collection: Cisco 1760, 2610, and a 2811 - with Call Manager, two Catalyst 3524's - one PWR, two 7920's and one 7960 SIP, and lastly the BIG DADDY a Catalyst 5505 Sup. II with a 24 port eth card.). I really enjoy watching you come up and work through random networking projects just because you enjoy the fun journey of learning and most importantly because you can and enjoy it! These are the exact reasons why I continue to collect devices and work on building a wild corporate sized network in my residential home lol. Please keep up the awesome work!
I would recommend turning off the modem's auto answer. The cisco should be able to answer on it's own. Using the modem auto-answer is really for attaching the modem to something that doesn't understand that there's a modem there such as a console port. For anything vaguely intelligent that's supposed to drive a modem, it should be listening for RING and responding to the modem with ATA to make it answer and also expect to hear that CONNECT line rather than be surprised when that shows up. Modem hardware auto answer is an archaic feature that was obsolete before the internet era.
You and your work are bloody brilliant. Thank you for your service and entertainment in prepping and publishing these videos Mr. Retro ❤
As someone who is currently on a networking / cyber security internship while i study for my networks and cyber degree, this old stuff is fascinating. It seems amazing how straight forward everything seems now even though I'm doing CCNA v7
Hey hey hey, awesome video dude! Love to see you messing with random hardware dude. Love it! Awesome job man.
Your channel is super informative. Thank you!
thank you!
This is so amazing to see, thanks for this journey through old tech 😁
Great video!
This is a topic that I actually know things about. Not the Cisco part but everything else. Here are my suggestions:
A: Make a serial sniffer cable. Take a straight DB25 cable that you connect in series with whatever you want to sniff/debug. Add two additional cabels to that DB25 cable, that in turn connect to the input pins of two serial ports of a computer (or perhaps your 8-port terminal server). Connect those two cables in a way that each sniffs signals from each direction. The simplest use case then is to just run two Putty instances on your computer, one for each sniffer port, but the better way is to use some dedicated software that indicates all flow control signals and whatnot too, and puts all text in the same windows with for example different colors to distinguish who sends what.
This is 100% the best DIY way to actually know what's going on on a RS232 connection. With this you can easily tell if for example the Cisco device and the modem are just echoing each others commands in a never ending echo ping pong loop.
B: For video creation purposes, and also perhaps to trouble shoot the noise other commenters mention, you can build a simple adapter to tap the phone line. A capacitor in series, say 0.1µF rated at 200V or so in series with a voltage divider with say 47k - 4.7k, and two "antiparallell" diodes across the lower resistor ("antiparallell"= two diodes in parallell, but turned in opposite directions). You can then connect an audio cable to the resistor-diodes combo (ground/shield to the wire that goes to the phone line) and listen using a line input on anything that has NO CONNECTION TO GROUND. I.E. a cheap USB sound card on a laptop running on battery power (and to be safe no other wires connected), or for that sake a 1980's boom box or whatnot.
Note that the speakers in the Sportster modems are terrible. They are more or less just a piezo buzzer that is hooked up to reproduce audio rather than just buzz. You can't distinguish correct clicks and whatnot from line noise.
C: As someone else have already stated - at least the 33k6 and newer modems already have error correction built in and thus any line noise or for that sake not-terrible compression issues on the phone line / ATA side shouldn't be a problem with those modems.
D: I also agree with the comment that suggest you try modem-modem connection with two computers (or two serial ports on the same computer) and make sure things are solid this way first. If you use some classic "modem" terminal emulator software you can also try sending files and check which speed you get, and any retransmissions (select ZMODEM for file transfers, it does error correction and whatnot and is generally the best choice compared to the older YMODEM, XMODEM and KERMIT in most cases).
E: You can also try connecting the AUX port on the Cisco device directly to a computer, maybe with a crossover cable, maybe not. You should be able to manually "emulate" a modem by pasting RING, wait for the Cisco device to say ATA and then paste CONNECT 9600 or similar in the terminal window. Note that you have to paste the strings as the slowness of manually typing might make the Cisco device think it's noise or whatnot. (Not sure if this is the case for Cisco devices but in general modem related software/firmware works this way).
F: If you give up on repairing the fully dead 33k6 modem, maybe ask Epictronic (UA-cam) if they are interested in having a look at it. After all, the USR modems are x86 based (IIRC they use the 80188) so they are fairly close to the PC's that Epictronics are already working on.
G: I've written this before, and I'm writing this again: I really wish/recommend that you get a classic office use PBX. Just make sure you get one that don't mangle the audio, i.e. either one that is old enough to connect the audio using analogue paths, or one with digital audio that is actually 8 bit and 8kHz sample rate. I'm biased by my own great experiences but if you can find a cheap Ericsson ASB 150/02, also known as Businessphone 50, 150 or 250 depending on enclosure size, they are a good choice. With a newer CPU card you can also connect to it using SIP over TCP/IP, while the older ones "only" do analogue, E1/T1 and it's proprietary desk phones. The minimum viable configuration for your use would be one CPU card and one ELU-A card (for connecting analogue phones/modems) but you would most likely also want a BTU-A card (to connect to your ATAs and whatnot, especially if you don't find one with a new enough CPU card to have SIP).
H: Keep up with all your great videos!
I've seen this older gear laying around for pbx to console admin of networking gear but I never got to use it. I'm going to enjoy this. Thank you :)
You can also use an AUX port to chain Cisco gear consoles together. You can connect the AUX from one to the CON of the other. Additionally, you can connect an AUX port to the serial port on older time servers (before they were IP-connected).
It's got to be the wire/connectors between the devices causing the issues. Try a different set of wires/adapters. If a new in box 56k modem is presenting the same issues as the other modems, it's not the modems.
"new" is doing some lifting there, especially considering the conjoined manuals. but i wholly agree with your logic
oh yes, friday night clabretro
You've gotta be one of the few creators who *really* scratches those itches for me.
Pure gold! Takes me back when I had to enter few AT commands in a pre-dial sequence that was sent to modem by I think WinSock.
One of my favorite periodic chores at work is going through and testing to make sure all our out of band management works, spending most of a day just dialing into terminal servers (Hayes commands and all) even calling the numbers to listen for line noise or intercept recordings.
I had that same modem and it died with all the lights coming on, I was more of a internal modem guy and the battle of the standard for 56k was between us robotics with X-2 and motorola with K56 was fun too. Had dual modems in the server with two phone lines and you could pool the modems together, that's the best u got back then before broadband but luckily we had ISDN in my neighborhood thanks to my neighbors company and he hooked us up with a 128k ISDN connection. The modem pooling was cool just like remote access with it here, miss the sounds probly the most and still remember all the AT commands lol. Great vid man and good work as always.
Our provincial telco still uses this method for managing their gear installed at customer locations. They use USR Courier business modems.
USRobotics still exists????????
@donwald3436 It's part of Cisco. The Couriers still exist and are widely regarded as the best PSTN modems ever made.
@@donwald3436 Yep. USR is still in business.
Ah modems. My childhood. I kinda miss the sounds they produced. I used to put a pillow over it to muffle the sound when i was calling bulletin boards at night so i didn't wake my parents 😅
I cannot wait to see the retro homeclab in action.
haha i like that retro console cable. not seen one of those since they came out with the console cable with usb to serial built in. Good Stuff.
I couldn't imagine how magical it had to feel to dial into a remote device back in the 90s.
We had a backdoor modem line at the ISP I worked for in the 90's, I believe it was attached to a Livingston Portmaster, from it we could telnet (pre-ssh!) to servers to fix things.
yeah, I had this kind of setup in 2000's. I even used GSM CSD once to fix things up when I messed firewall config.
Those problems with the modem scream degraded capacitors to me. Any piece of equipment like that which takes low-voltage AC in will have a small bridge rectifier on the input directly after the connector. This then rectifies to 9 * 1.414 =12.7VDC. The capacitors directly after the bridge rectifier have to be good quality to provide a nice, stable DC supply that, critically, can provide large current spikes when needed - for example when trying to switch a relay. If this capacitor, or the bypass cap on the 5V regulator, have gone bad then the digital electronics could be seeing a large amount of ripple on their power rails which causes all sorts of crazy havoc with CMOS circuitry. If you've got even a cheap oscilloscope (even one of the really, really basic things like the Arduino-scope would be acceptable as all you're concerned about is under 500Hz) and you probe the voltage rails while it's on, that will instantly tell you what's wrong. Additionally, if you replace the caps, you can safely just connect a 12VDC adapter to the modem with no issues, assuming it's laid out as I described.
++ sound advice here!
I just realized something else -- the issue could also be inadequate or intermittent ground. When you noticed the power supply cable was damaged, did you do a full continuity check? Or check to see if the lines were shorted together at all? That could also be causing some of your issues, and would explain why the data lights are blinking randomly -- the current for the circuit is returning via the grounds on the serial port instead of through the power connector. However, it still could be bad capacitors. I would definitely try using a different power adapter if you have one handy just to eliminate that as a potential cause.
Oh, and I forgot to explain at the end of my original comment *why* you'd want to switch to a DC supply. First, they're cheaper and easier to find, especially in 9V/12V versions. Second, the input stage doesn't have to deal with the AC ripple after rectification, which means the main supply capacitors have an easier time overall. And third, typically a good quality DC power brick will have more protection than the cheapo AC wall warts, which are usually literally just a small transformer with a fuse... DC supplies often have over/undervoltage protection, overcurrent protection, overtemperature, etc...
Oh, I should have waited till the end of the video to comment. Yeah, I have a feeling most of the issues are coming from flow control. Just turn flow control off entirely on both ends.
Back in the late 90’s - mid 00’s my office had Frame Relay with modem backup to RAS server. Worked pretty well and kept us connected. We weren’t web surfing over that connection strictly database stuff.
You can piggyback from an AUX on Router A to a Console on Router B, SSH/Telnet to Router A, and then dial into Router B. We used them more for that than anything back in the day.
Two things. Do a factory reset on the modems so you have a known starting point. Second, repin your DB-25 so you can use a standard Ethernet cable.
Cisco used to sell an six cable but it was part of an expensive kit. 3rd party companies made the cables for $20 each.
I used to build these configs for remote access into a data center. It kept me from having to drive in 100 miles at 2am when a router or switch crashed.
It’s been a long time since I thought about doing this stuff. I had a stack of the nice Hayes 2400 baud modems in those nice extruded aluminum cases. Good memories /cough
My Dad used to work for a big bank and would bring these home when they were “retired”. My friend and I had a Cisco 2500 at each of our houses and used to play LAN games over dialup.
Believe it or not, my infrastructure at work actually has a couple of routers set up with dial-in access via 56K modems today. We have no admin access to these routers so our ISP manages them for us and utilize the dial-in function only as backup if they can't log in via the T-1 WAN interface (yes, we also still have T-1 links). We had to get standard analog POTS lines run for each router, assisted in setting up the modems, etc... this was a few years ago but yeah, we still utilize this technology today.
this is so cool this feels like a good use to dial up in 2025
Its funny my day job is decoming old pots equipment and all I do is watch your videos on setting them up.
Sounds like the two of you should get in contact :D
Very nice, I'm glad people seem to be getting back into modems these days. I've got plans to set up a dial up ISP that you can access over a VoIP ATA if you should so desire.
Never thought about using an ATA in that manner, port to port locally, definitely going to try that. Thx.
I swear I remember there being a rack mount for the Hayes SmartModems, think you had to take the modem apart to mount them in it. Held 3 modems in a rack U.
You have truly fascinating gear. Stuff I always wondered how it worked. Such as dial up networking. Your various server stuff is really cool. I can never afford to mess around with ancient gear, so this is the next best thing. Well, that, and I don’t have the room. Ok, ok. I hate clutter.
You are causing me to remember some serious late nights sat in data centres in the nineties trying to get this stuff working. One thing that caused me enough issues i still remember it, check your your RJ45->DB25 converter connects *both* the middle ground pins on the RJ45 to pin 7 on the DB25 some did not and some DTE only used one pin on the RJ45 which caused all manner of insanity with signals which looks remarkably like your strange behaviour.
My knee-jerk is to say turn off all flow control while testing. It really only matters when you're doing high-throughput and there's a chance of a buffer overrun. He won't see that when typing commands at a console prompt.
Also, as I recall, the high-speed modems (anything faster than 9600) worked best when the serial ports were fixed at a speed that was faster than their best connection speed...
It's been nearly 30 years since I used a modem. We switched to ISDN BRI asafp. I feel old.
lol with v.92 us robotics? LOVE IT thanks for sharing sir!
AUX (audio lol)
13:55 I remember my USR 14.4 modem having some built in help for the AT commands, I think the command for it was AT$. It would print a bunch of text explaining what most of the AT commands do. Also ATS$ would tell you what all the S-registers did.
For a "Networking" class I took for my CS degree I wanted more of a challenge, so I used an Arduino with a temperature sensor that would log the data to a PHP script and a database, but the Arduino was connected to a GMRS modem/module and I stumbled though sending AT commands to send a GET request with the data in the URL of my PHP site. I had no clue why those commands worked but I presented first to the class with the most complex project and didn't have to do anything the rest of the week.
In both datacenters at my previous employer, they used USRobotics Courier modems in the AUX port of the Cisco Routers. They are long and slim. Those modems are supposed to be the best of the best and survive poor line conditions, etc. Might be worth a shot. Can’t ever have too many modems. 🤷🏻♂️
24:43 it looks like the paper became moist at some point in time in the past and dried up again, causing it to stick. You could reverse this probably by steaming the whole package, i.e. bring water to a boil and then place the whole package on a sieve above the water so the steam can penetrate it. Once it's soaked again you should be able to carefully pull the pages apart and then let them dry spread out.
Nice! I have 2 broken ATA adapters, and cannot configure them, but one of them still has the 48v on the RJ11 although it will not give the dialtone, but the voltage is all that you need. You dont have to degrade the connection passing it through voip filters, in this way, it connects the best speed the modem has at optimal conditions. All that you need is a RJ11 phone line splitter, that beige adapter that has a male and 2 females RJ11, so you plug the adapter into one of the MUTE ATA ports (you don´t want the dialtone, because it will mess the connection, disable the service) just to get the voltage and the 2 phone cables in back of the adapter, so the modems will listen eachother. The 2 modems must be on the same ATA port! If you dont havean adapter, just mend together 3 RJ11 cable ends, plug one on each device! Now you need to pass some AT commands, ATX0DT123 on the modem dialing, X0 disables the dial tone detection, so it dials right away, without complaining No Dialtone and on the other modem the command ATA to answer the call. I Still Have my precious USR Courier from the old times! I think it will never connect 56k X2 or v.90 because the telco did some trickery for it to work, but it will connect v.34, the com port speed must be configured 115.200bps. You can try using some Terminal program, I use the classic Procomm Plus! It also supports telnet BBS´s that are still around. I have it installed in a Win98 oracle virtualbox, machine and it can access the COM1 port on the host to use the modem.
Former telco ISP architect here. RS232 is such a pain. We had a main Sun server (back before redundancy was a thing) that ran everything but authentication. If you accidentally knocked the DB25 out, the server would shut down. Fun times.
I'm now forever calling an octal/octopus cable a squid cable! 😅 Love the content, clab! Keep it going!
That 1200 Baud terminal text appearing reminds me of War Games (1983), though the technology there was probably even slower than that!
The Teal 33,600 and "Sportster 33.6 Faxmodem" is such a vibe, a moment in time like '95? '96? I had this exact unit and moving up from a Hayes 9600 felt like a monumental change, I was holding the future in my hands. I don't quite recall what the deal was with their Sportster branding, but it felt like it was meant to be portable, because it was so sleek and stylin.
I had the same problem with my fax through the SPA, I had to change the "Preferred Codec" (G711U) and "FAX CED Detect Enable" (YES) this fixed so much, but if you can hear a noise on the line then you might need to clean a cable or keep it away from SMPS
One other thing. If you’re in to hacking modems, you will enjoy poking Wi-Fi access points at the hardware level. They use the AT command set as well. They have a few extra commands but same idea.
Ah, so THAT's what the AUX ports on the routers in my Cisco CCNA study lab kit are for!
For everyone thinking AT-commands are arcane, quite a few 5G modems are still controlled by AT-commands. The command set has been extended multiple times, but still, it's based on the same old Hayes AT command set.
cathode ray dude mentioned
Never trust a premade cable or adapter! Troubleshooting serial connections almost always requires a simple breakout box that goes between the DB25 socket and plug. It's nothing more than a bunch of LEDs and possibly jumper cables to reconfigure the connection.
To connect a DTE (Data Terminal Equipment, the router) to a DCE (Data Communications Equipment, a modem), you need to connect GND, Rx, Tx, RTS, CTS, DSR, DTR, CD and RI all straight through (that's one more than an RJ45 plug can provide; at least one signal must be missing from the router). CD (Carrier Detect) is important because it tells the DTE that the connection is finally established. RI (Ring Indicator) allows the DTE to answer calls whithout resorting to the auto answer setting of the modem. RTS and CTS were originally meant to turn on the transmitter hardware (Request To Send) and signal back its state (Clear To Send). They're typically used for hardware handshake in later implementations like smart modems. DSR and DTR are more or less static signals to indicate that the devices are turned on and ready.
Smart modems are special because they can autodetect the baud rate of the serial interface by monitioring the receive line for the "AT" command. The speed between the modem and the DTE is independent from the connection speed over the telephone line. Some modems even add data compression to the latter. This makes handshaking between the DTE and the modem absolutely neccessary. It's always a good idea to set the DTE baud rate to a higher value then the actual connection speed.
As others have already pointed aout, in order to troubleshoot the runaway Rx/Tx blinking you should check for local echo settings on each side of the connection. This may create a tight feedback loop, just like a microphone close to a speaker. You can debug this by feeding one of the data lines to an additional serial interface and use a terminal application to monitor the data. Maybe you should hunt for an actual line monitor which might come handy in other cases, too.
Its because you're going over a voice gateway...
I have the same model Linksys ATA box and have no trouble using it for dial-up modem calls. Like he said, it has to be setup correctly.
Honestly, I believe the advent of the remote access “feature” was what sparked the rivalry between network engineers and security engineers. As an old-school (late 90s) security engineer, I can’t help but love, but also at the same time hate, just a little bit, this video.
i enjoy Clabretro and at 5:36 those Cisco IP phones I have seen those in schools but those phones could dial an outside line with 9 to reach an outside line and then a phone number and mostly those phones could call internally other phones in schools offices and classrooms
Some notes - BUSY is generated by the phone network in analog settings. If you hear a busy signal on an analog line, the network (ATA in this case) is giving that signal. A black screen after CONNECT usually indicates a flow control or cabling issue. Easiest thing to try is turning off all flow control. At slower speeds, you can usually get away without having it. If that doesn't work, check your cabling, most likely your adapters. There's multiple types of serial cables/adapters and they aren't all interchangeable.
I have a rack in my basement called The Lan Before Time, with some 386 and 486 machines, after seeing this and another person I got a 3825 to get dialup and token ring working.
haha awesome
I still have my USR Sportster Flash v92 modem from way back in 1997! Now from some vague memory to just have the AA enabled you normally need some sort of host otherwise yes you can dial in but nothing passes between the two... It's been a very long time since I have used AT comands like that!
Wow. That 1200 baud made me remember my old bbs days frpm my 2400 baud modem..
Try dialing into the modem while it's connected to your computer (from USB modem to old modem). That way you can check the modems can connect without fail. Also fun-fact some US Robotics modems didn't need dial-tone to connect to each other -- If you issue dial command (ATDT) on one and answer command (ATA) on the other they will connect without a physical ATA unit in between.
I would love to see a CME video. You can setup a small PBX with that 7960 and those linksys ATAs with a Cisco ISR router!
Once ran a BBS with a Fido node. Seems an eternity ago. One thing that jumped at me was the IO errors on the router. You don't appear to have a serial buffer. Back in my day, the 16550UART was basically table stakes for modem or serial comm port. This is part of the "hardware control" in the connection. Why the router doesn't have a buffer is almost certainly because they expected the user to have that AUX connected to a device with an external buffer. Perhaps a hub of some sort for the AUX lines. Perhaps what your octopus cord plugs into. I don't know how to get around that for the router. But on your PC side, the buffer needs to be on the PC. Most PCs with a 9-pin serial port have a UART because go hand in hand. For a PC without native serial ports, we got ISA or maybe PCI cards with serial ports. They also made PCMCIA cards, I believe. I use an old Dell D630 notebook with a serial port for all my modem tinkering. It has a built in modem but I own a stack of external modems like the Courier and multiple Hayes and Practical Peripherals externals that I love using. Nothing sounds better than a V.FC connect tone sequence. Man. Anyway, back to your PC, a typical serial to USB dongle might not have a buffer, nor would any USB port. It's not something needed these days. But the router needs it, apparently. Workaround: slow down the router baud rate until the IO errors stop. I would get a really good modem like a Courier first and then try going to lower and lower baud rates until it stops having those errors. Good luck. Caveat: I am old enough to no longer remember important stuff.
This is sweet! I have a spare 2621 router lying around and I wonder if I can do dial up stuff with it.
I should mention that I do have a voip server running CUCM 14 and Unity Connection 12.5. I also have an Asterisk server as well.
The USB, USR 33k and V.92 modems have V.42, which uses LAPM or MNP to detect any noise and transmission errors, and retransmit faulty data. Usually this is enabled by default, BUT your line is either so noisy thst it falls back to unprotected, or LAPM is disabled in the permanent configuration of your modems. Try playing around with the +ES and \N commands, write the config with &W to permanent store (or check with +ES? what the setting is). During connection establishing, it should display CONNECT (speed) LAPM or V.42. Example command sequence to try:
AT+ES=3,2,4
AT\N2
AT&W
This forces the modem to negotiate either LAPM or MNP, and quits if error correction can't be established. You need to do this on the V92, 33k and USB modem, and on both sides. The 9600 modem can't do this.
Check the documentation of your modem types if they have the values different, but the ones I gave you are pretty standard.
you can simulate phone network with a 48vac pulse to simulate a ring. you can simulate dial tone with 9vdc on the pair.
For once you and I seem to have some of the same equipment!
I have a US Robotics 33.6K sportster just like yours from 1995, yours is in a bit better shape but it was neat to see someone else with one.
Mine I got second hand from an old employer, it used to run hyperterminal for system management of a few sites....
The modem was connected to a IBM Windows XP machine and was in production until its retirement in 2017. Had the modem ever since. Once in awhile it comes out for use. At one point it even was in my tech bag and was used as a butt-set. Not ideal, but it got the job done until I could afford a proper unit.
Anyway... modems.
I think I've been watching your channel now for.... 2 years? 3 years? Something like that? Anyway, your comfort with the Cisco terminal has grown a lot, not that you were bad with it or something like that before, but it's obvious that it's far far less of a strange black box that you might not be comfortable with, great job!
Occasionally I visit classes working with Cisco equipment and it's always neat to see the students getting more comfortable with the Cisco CLI, just something neat about seeing it, hard to explain.
Anyway, keep up the good work!
Awesome video! I'd love to see a POTS line intead of a rj11 though :D
My favorite Renton man!
Try using an ethernet cable as a phone cord, like just take 2 pairs from cat 5e or cat6 cable and terminate rj11 connectors on there, the twisted pair may eliminate some noise on the line that was heard at one point
Try turning off local echo on the modem connected to the router. The modem and router are probably getting into an error feedback loop and that’s the RD/SD activity you’re seeing. After enough of this it might cause the router to stop talking on the aux port.
You’ll need to be to write your modem config so it’ll persist on power cycle.
AT commandset is also used in USB cellular modems. Disk in, change settings on it.
Its crazy how some guys ridiculous Monday morning idea was built into millions of products. 😂
Look into an ADTRAN 908E, it has full internal TDM switching and supports dialup between extensions REALLYYY well. It’s managed just like a Cisco router thru the CLI or you can enable the webui which is helpful
So weird, my work had a 1921 router at a remote location I visited earlier last year and despite the ISP no longer providing dial up, it still had a cable hooked into the AUX port going into a still powered on dial up modem. Wow.
Before randomly plugging in old wall warts (power adapters) into any equipment, ESPECIALLY the old linear types, you need to check their voltage output first. If they're DC, you also need to check the ripple.
Transformers used in these power adapters degrade over time from heat and vibration, as well as the pressure from the windings in the core. What eventually happens is that the enamel coating on the wire will disintegrate or move around and cause windings to start shorting out. When this happens, the output voltage will start rising, and it can get alarmingly out of spec.
I found this out the hard way a few decades ago with my Sega Genesis. I went to turn it on one day and the console would run for a few minutes and then crash repeatedly. After investigating, the LM7805 regulators were smoking hot and had started desoldering themselves from the logic board. Further investigation showed that the original Sega branded wall wart that was originally 9 volts was 27.5 volts. This shocked me at the time, so I started checking all of the old linear type wall warts I had at the time, and I found that none of them that were older than 5 or 6 years were anywhere near what they were supposed to be. My oldest wall warts at the time from the late 80s and early 90s were all over 15 volts, when they should have been 9 volts or less. Some were over 20 volts, and the Sega one the 27.5 volts.
After testing hundreds of wall warts over the years and doing destructive failure analysis, I've come to the conclusion that they all will fail by design. Whenever I see an old wall wart like the ones in the video, they get trashed and replaced with a modern SMPS power supply. That is unless it requires AC like the modems here, in which case I'll just buy an off the shelf transformer and make my own housing for it and trash the old unit.
I would hazard a guess that the working US Robotics modem that just recently died was killed by the wall wart blasting it with voltage that's too high. The old one that just lights up everything was probably blown up by a lightning strike or other power surge, they were particularly susceptible to that.
The first modem I ever owned was a 1200. My Dad had a 2400, but I was able to score the 1200 internal ISA card for my own Blue Chip clone. Yeah, 1200 was painfully slow.
That's quite a journey :D
AA flashing like that is a visual indication of an incoming ring voltage. I think one of yhe S registers tells the modem to pickup on a certain number of rings. This was so you could have other equipment on thhe same line like a fax.
If that is a SPA-2102 I have a video on my channel for unlocking locked ones, FYI The nice thing about 300baud modems is you can type faster than they transmit makes you feel like a super hacker