Original IBM Serial Card 1502074 settings?

[Axel Griese]

Anybody have the docs for the U5 and U15 setting on the Original IBM PC Async Card 1502074?

I am particulary looking for the DB25 pinout for when it's in TTY Current Loop mode, and how to set U5 and U15 for that mode.

Right now I have:

U5: J1-J4 open, J5-J8 closed
U15: J9 and J10 open, J11 and J12 closed


Thanks.

AG

 

[Chuck(G)]

The Original async adapter had two plugs; one for address and the other for current-loop-vs.-RS232C levels.

Are you saying that you're missing the plugs?

 

[Axel Griese]

I have the plugs, just not sure if they're in the right position for TTY current loop.

Also, I don't know which pins to use on the DB25 for current loop. I'm assuming it's differnt pins than those used for RS232 but i don't know.

 

[Axel Griese]

Ah, I see the pinout in your link - TX on 9,11 and RX 18,25. Thanks.

My jumper plugs are different than what's shown in the linked document, but i guess I can figure that out by trial and error.