V.24 Port Pinouts

[Twisted_Pear]

I haven't got my hands on a DIU manual yet but does Motorola list which pins of the RJ-45/8p8c port are what when using V.24?

RS-232D defines them as follows and I hope Motorola follows this format.

1 DSR (or RI)
2 DCD
3 DTR
4 Sig GND
5 RxD
6 TxD
7 CTS
8 RTS

I'm looking at doing some linking with simple RS-232 RF modems instead of more complex conversion and backhaul solutions.

[515]

The pinout you have there is similar to the V.24 card's RJ-45 jack on the front of the Quantar. The V.24 link is a 9600 bps synchronous RS-232 connection, so you have clock signals to worry about. The V.24 card RJ-45 jack pinout on the front of the Quantar is:

1 -- RCLK
2 -- CD
3 -- TCLK
4 -- GND
5 -- RxD
6 -- TxD
7 -- CTS
8 -- RTS


For the DIU, you'll use the COMM connector (DB-25) on the back. The DIU COMM connector seems to follow the standard RS-232 pinout:

DIU COMM
DB-25 pin:

2 -- TD (to Quantar)
3 -- RD (from Quantar)
4 -- RTS (to Quantar)
5 -- CTS (from Quantar)
7 -- GND
8 -- CD (from Quantar)
17 -- RCLK (receive clock from Quantar)
24 -- TCLK (internal TX clock to Quantar)


I've tried to use a couple of MaxStream XTend-PKG 900 MHz modems for the DIU/Quantar V.24 link, but since they don't support synchronous serial or true full-duplex, they didn't work. They do work fine on the Quantar's RSS port (9600 asynchronous), though. It's kinda neat being able to program the Quantar without going to the site!

Let me know if you find some kind of inexpensive wireless modem that works with the V.24 link. The hardest part will be finding something that supports synchronous serial and true full-duplex. The Quantar and DIU can generate the clock signals, or the modems will have to... This is what the "internal/external clock source" setting is for in the Quantar and DIU RSS.

I don't think you'll have to worry about the RTS, CTS, or CD signals, though.

I have recently had success using Juniper Networks CTP (circuit to packet) devices to link a Quantar and a DIU via an IP connection. They're not exactly cheap, though.

Good luck!

[Twisted_Pear]

Awesome info! Thanks. I know there's got to be an easier way than what Motorola specs out.