Hi, All,
Going through a pile of stuff in the basement, I uncovered a hamfest
find from a couple of years back - a short stack of frontpanels for
an IBM leased-line modem. I picked them up because they have a 4x5
keypad with the keys marked 0-F (and a row of blanks). That alone
made them worth it, but having looked at them in detail, it might be
fun to adapt them as is rather than part them out. Cursory
examination reveals
o a 16x1 VDF display with "british flag" segments
o the aforementioned 4x5 keypad
o several DIP parts that may be equivalent to ULN2803s that seem to
drive the VFD segments
o some sort of TI-branded 40-pin DIP microcontroller
o a 34-pin pigtail cable to the modem
Since most of the cable pins are clearly grounds and Vcc, there
appears to only be about 12-14 non-power signals which disappear into
the microcontroller and the (I think) transistor arrays.
What I'm hoping to find is any sort of documentation that might reveal
to me how the modem MPU drives the front panel. I don't have the
modem, so I can't scope the signals. I can produce a
reverse-engineered schematic from the real board up to a point, but a
mysterious MCU is difficult to scope out.
Worst case, these were worth the $1 I paid for them just for the
parts. Best case, I can stick some sort of MCU on the 34-pin
connector and talk to that from a "real" computer. Second best case,
I could dike out the TI MCU and wire something in its place.
So... google did not reveal any obvlous locations. Does anyone know
of any secret repository of IBM hardware docs?
Thanks,
-ethan
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