pinning serial connectors

[NeXT]

I'm setting up a switch box so I can control eight SGI and Sun workstations from a single VT510 serial terminal and today I got a bunch of adapters (http://www.ntikvm.ro/images/adapt-db25m-rj45f.gif) that let me use regular RJ-45 network cable as the serial cable. They are repinnable so I want to set them up so I can use them for the task and I got eight conductors to work with. Now, for DB25 connections, which pins are important to the proper operation of the serial terminal?

http://www.chimica.unipd.it/luigino.feltre/pubblica/unix/rs232/rs-232/rs232/db25_pin_name.gif

EDIT: I'm finding pinouts for these adapters on google but I don't know if they are either a) to RS-232 stndards and b)what I want.
Apparently what I'm looking for falls under the Yost Serial Device Wiring Standard (http://yost.com/computers/RJ45-serial/). About halfway down that page they mention DTE devices which I'm assuming I am using and that the listed pin to pin listing is correct and what I want. Is this correct and do I have to worry about this for what I'm planning on doing?:

Some DTE devices require the DSR (Data Set Ready) signal. This signal is usually provided by the DCE device. If you have a DTE device (such as a terminal) that requires the DSR signal, wire pins 20 and 6 (4 and 6 on a DB-9 connector) together. This way, the DTE device will receive the DSR signal from itself when it asserts the DTR signal.

[Chuck(G)]

Depends on the application.

In general, RxD, TxD, Gnd, RTS, CTS, DTR, DSR for RS232C async. That's 7. Many async apps can get by with only 3 lines (jumper RTS to CTS and DTR to DSR on each end), so you could use RJ11 cable if you wanted to.

But if you're doing sync, you'll need to pass the clock. If you're using something that depends on the modem hardware signals, then DCD and RI.

Believe it or not Radio Shack used to sell these things too, but for an RJ25 (6 line) jack. I've still got a couple.

[NeXT]

Depends on the application.

In general, RxD, TxD, Gnd, RTS, CTS, DTR, DSR for RS232C async. That's 7. Many async apps can get by with only 3 lines (jumper RTS to CTS and DTR to DSR on each end), so you could use RJ11 cable if you wanted to.

But if you're doing sync, you'll need to pass the clock. If you're using something that depends on the modem hardware signals, then DCD and RI.

Believe it or not Radio Shack used to sell these things too, but for an RJ25 (6 line) jack. I've still got a couple.

Um, I just wanted to go from computer serial port to terminal with the switch in between. There won't be any modems or special hardware involved and all the systems use the bog-standard "9600, 8, n, 1" communications setup.
I'm still totally confused. It could be because I'm tired. I don't know.

[Chuck(G)]

Use the 7 lines that I first mentioned.

If you're going computer-to-computer, or computer to terminal (both are DTE) then you'll have to do a "null modem" or crossover of the lines, thus:

Gnd->Gnd
RxD->TxD
TxD->RxD
RTS->CTS
CTS->RTS
DTR->DSR
DSR->DTR

So one system sees the other's transmitted data as its received data, etc.

[patscc]

It might be helpful if you can scrounge up a RS232-C breakout box. This let's you rewire the connection on the fly with jumper cables, which can be handy to figure out what works and should be quicker than constantly re-pinning connectors.
patscc

[NeXT]

Okay, I see it now.
So I'll directly pin all the adapters and then for the line that runs to the terminal I make it the null modem cable so it will properly communicate.

[ahm]

What you seek is "Zonker's Greater Scroll of Console Knowledge": http://www.conserver.com/consoles/

[NeXT]

What you seek is "Zonker's Greater Scroll of Console Knowledge": http://www.conserver.com/consoles/

Hey, that is an awesome page. Anyways, I got the connectors I needed pinned finished and I'm running several systems no no problem so it looks like it worked.

[Terry Yager]

Yeah, thanx, Andy. I had that bookmarked long ago, but somehow lost track of it.

--T

[Terry Yager]

If you're going computer-to-computer, or computer to terminal (both are DTE) ...

These are the rules that apply. Except when they don't. Then there are other rules.

(Sometimes, computers are wired as if they are (*gasp*) computers).

--T

[Chuck(G)]

These are the rules that apply. Except when they don't. Then there are other rules.

(Sometimes, computers are wired as if they are (*gasp*) computers).

But not PCs. PCs know their place.

So if you hook said DCE computer to a modem, which is clearly DCE, you have to use a crossover cable. And what is DCD and RI supposed to mean on a computer configured as DCE?

[NeXT]

Well now that I got a majority of the systems sorted away with their connections I need to find a half dozen mini DIN-8 to DB9/25 cables. Oh boy that will be fun. :p

[NeXT]

Here we go again.
This time I have an Alpha LED display (PPD220RED) but I have to build a serial cable for it.

It uses an RJ11 to DB25 adapter to either connect to a computer or to a modem and unfortunately I only have the adapter that connects to a modem and I need the other one.

It's (the RJ11 to DB25 adapter) pinned so that Pins 2, 3 and 7 (TxD, RxD, Gnd) go to the display and 6, 8, and 20 (DSR, DCD, DTR) are wired together and do not go to the display.
I need assistance pinning a new adapter so I can plug the display directly into a computer and then run it from there.

[NeXT]

Mods: Cleanup requested in aisle seven.

Looks like they are bots roaming the site again.

[Chuck(G)]

Wow, that's a clever spam, I've got to admit.

At any rate, why not use the adapter you have and simply interchange pins 2 and 3? It should work.

[NeXT]

Really?
is that all I have to do to convert a modem adapter into a pc adapter?