17 Sep
2008
17 Sep
'08
1:44 p.m.
I've got one of the three port H-89 serial boards and I think I've got the
connector for port 330 wired incorrectly.
The CD bit is never set even when carrier is present (cable and modem
known good). Does anyone out there have the pinouts for the card-end of
the internal RS-232 cable that I could get a copy of?
According to my Z90 schematics (same machine AFAIK). the wriing for the
intenal serial port cables is the same for all 3 ports -- the difference
between DTE and DCE wiring is on the PCB. I'll specifically give the one
for the DTE port at addresses 330-337 :
P605 (PCB connector) DB25
5 ---- Rx Data --------3
9 ---- CTS ------------5
11 --- DSR ------------6
15 --- DCD ------------8
3 ---- Tx Data --------2
7 ---- RTS ------------4
14 --- DTR ------------20
13 --- Sig Gnd --------7
1 --- Prot Gnd --------1
According to the scheamtic, The DCD pin on the DTE connector goes to pin
15 on P605, then via L617 to section b (pin 4) of U609, a 1489 chip. The
output of that (pin 6) goes to RLSD/ (pin 38) on U604, an 8250.
-tony