15 Dec
1999
15 Dec
'99
3:01 a.m.
"Scott G. Akmentins-Taylor" <staylor(a)mrynet.com> wrote:
FYI Chuck, my MV IIs are quite happy using only the
transmit, receive
and ground when connected directly to my PCs. This is simply:
MV II PC
2 ----------- 2
3 ----------- 3
7 ----------- 7
I don't see how that could work (reliably). If that's for a 25-pin PC serial
port, you've got 2 and 3 swapped. If it's for a 9 pin PC/AT style port,
ground needs to be on pin 5 rather than 7. In the latter case, I can imagine
that things might sort of work as long as the PC is driving RTS negative, but
I wouldn't want to count on that.
25-pin 9-pin
Function DTE PC/AT uVAX
-------- ------ ----- ----
TxD 2 3 2
RxD 3 2 3
RTS 4 7 4
CTS 5 8
DSR 6 6 6
SG 7 5 7
CD 8 1
DTR 20 4 5
RI 22 9
Since both PCs and uVAXes are DTE, the TxD and RxD lines between the two
need to be swapped (as do some handshake lines) to form a null modem.