IBM Series/1 part number 6523105

This is a part of a IBM Series/1 mini computer.
Who can identify it's function?
There's a brochure about the Series/1 at: www.dvq.com/ads/IBMSeries1.pdf

[@MrPaulie1340]

My guess is this is an adapter for a 4973 line printer, Going by the width of the cable connector that goes in the handle side of the card.

[@muckeyduck3472]

Looks more like a 4978 display adapter to me.

[@neilolif]

Hmmm.., I wish I had kept my Series 1 MES parts list. :(

[@QuaaludeCharlie]

1 megabyte 8 inch floppy disk drive Controller , I,m guessing though :) QC