Alex@rtnVFRmedia Suffolk UK is a user on social.tchncs.de. You can follow them or interact with them if you have an account anywhere in the fediverse.
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I think this might be an old RAM disk card with a serial port?
@craigmaloney looks like expansion RAM board for an IBM PC or compatible.
What gender is the 25-way D-sub connector on the back? from memory (over two decades now) a *male* connector would be a RS232 (serial/COM*), whereas a female one would be parallel (LPT*). Parallel printers were also common back then.. could well be the item below which had both (connector on board was COM1/2 and a ribbon cable connected to another 25way female D-sub for LPT1/2)
@vfrmedia It has a 16450 so I'm thinking it's a 25 pin serial port.