Null Modem Wiring Schemas
-------------------------
From gjohnson@dream.season.com Mon Oct 28 09:59:58 1996
Newsgroups: comp.terminals
Subject: Pick a number of wires, almost any number . . .
Date: 23 Oct 1996 22:13:28 GMT
During my search for the best thing to do with six wires I
helped someone that only had three and got the following
response, which might be interesting to readers here.
--
Gary Johnson "Rosebud . . ."
gjohnson@season.com Freedom?
CAMPAIGN '96: Juck 'em if they can't fake a toke.
From: Francesco Potorti`
Newsgroups: comp.os.linux.networking
Subject: Re: TCP/IP over null modem?
gjohnson@dream.season.com (Reality is a point of view) writes:
I wish I knew which connections were best when there are six
wires available.
I have this note. I copied it from various sources. The only one I
really tried is the last one, to be used while connectin two PCs with
the DOS program whose name I can't remember (standard with msdos > 5.0)
7 wires null modem connections
for V24 protocol on RS-232
DTE DTE
2 [>]------\ /------[<] 2 TX
[ ] \ [ ]
3 [<]------/ \------[>] 3 RX
[ ] [ ]
4 [>]-\ /-[<] 4 RTS
[ ] | | [ ]
5 [<]-+---\ /---+-[>] 5 CTS
[ ] \ / [ ]
6 [<]----\ / /----[>] 6 DSR
[ ] \/ \/ [ ]
7 [-]-----/\-/\-----[-] 7 GND
[ ] / \ \ [ ]
8 [<]---/ / \ \---[>] 8 DCD
[ ] / \ [ ]
20 [>]----/ \----[<] 20 DTR
3 wires null modem connections
for V24 protocol on RS-232
DTE DTE
2 [>]------\ /------[<] 2 TX
[ ] \ [ ]
3 [<]------/ \------[>] 3 RX
[ ] [ ]
4 [>]-\ /-[<] 4 RTS
[ ] | | [ ]
5 [<]-/ \-[>] 5 CTS
[ ] [ ]
6 [<]-\ /-[>] 6 DSR
[ ] | | [ ]
7 [-]-|-----------|-[-] 7 GND
[ ] | | [ ]
8 [<]-+ +-[>] 8 DCD
[ ] | | [ ]
20 [>]-/ \-[<] 20 DTR
Null modem on the MISCO catalogue (DTE)
DTE DTE
1 [-]---------------[-] 1 GND
[ ] [ ]
2 [>]------\ /------[<] 2 TX
[ ] \ [ ]
3 [<]------/ \------[>] 3 RX
[ ] [ ]
5 [<]-\ /-[>] 5 CTS
[ ] | | [ ]
6 [<]-\ /-[>] 6 DSR
[ ] | | [ ]
7 [-]-|-----------|-[-] 7 GND
[ ] | | [ ]
8 [<]-+----\ /----+-[>] 8 DCD
[ ] \ [ ]
20 [>]------/ \----\-[<] 20 DTR
Null modem on the MISCO catalogue (DCE)
DCE DCE
1 [-]---------------[-] 1 GND
[ ] [ ]
2 [>]------\ /------[<] 2 TX
[ ] \ [ ]
3 [<]------/ \------[>] 3 RX
[ ] [ ]
4 [>]-----\ /-----[<] 4 RTS
[ ] \ / [ ]
5 [<]----\ \ /----[>] 5 CTS
[ ] \/ \/ [ ]
6 [<]-----/\ /\-----[>] 6 DSR
[ ] \ [ ]
7 [-]------/-\------[-] 7 GND
[ ] / \ [ ]
20 [>]----/ \----[<] 20 DTR
Null modem for PC
DCE DCE
2 [>]------\ /------[<] 2 TX
[ ] \ [ ]
3 [<]------/ \------[>] 3 RX
[ ] [ ]
4 [>]------\ /------[<] 4 RTS
[ ] \ [ ]
5 [<]------/ \------[>] 5 CTS
[ ] [ ]
6 [<]-----\ /-----[>] 6 DSR
[ ] \ / [ ]
7 [-]-------\-------[-] 7 GND
[ ] / \ [ ]
20 [>]-----/ \-----[<] 20 DTR
--