26 Nov
2007
26 Nov
'07
10:54 p.m.
However, my 5271 originally (a long time ago, before I inherited it) had
a card with a BNC connector on the back, which sounds like it may have
been a host interface. Unfortunately I didn't get the card when I
inherited the machine (the previous user removed it to install a modem
in its place), so I can't provide more info. There's a chance I may be
able to get in touch with him over the holidays, and if so I'll see if
he still has it lying around somewhere...
I have something here that might be related, althoguh I don't think it
was made by IBM.
It's a full-length 8-bit card with a single BNC connector on the bracket.
The outer of the BNC is isolated fro mthe bracket. The silkscreen on the
board gives the name 'PC/3278'
There's a 2*30 set of edge fingers at the top front of the PCB pointign
upwards. THe board is of such a shape that a socket could be fitted here
and the cover would still go on the PC.
The main components on the board are :
8X305 microcontorller
3 24 pin EPROMs (I can't see the type without peeling off the labels)
8K of SRAM (4 off 6116)
DP8340 and DP8341 (I have seen these chips befroe in 3270-related devices)
Lots of TTL
8MHz and 18.868MHz crystaks
-tony