Cable Selection for serial data transfer
Cable Selection for serial data transfer
(OP)
Hello, I am looking to extend the cable length between a radio modem and the serial port of a copmputer to about 30m, What type of data cable is suitable for this application? I have had a quick browse through the RS catalouge but there is many different cable options which has made the choice even harder.
Thankyou
Thankyou





RE: Cable Selection for serial data transfer
If you have an RS232 interface between the computer and the modem it's not good for more than about 10 metres at a maximum data rate of 9600 bps, as - in theory - the line drivers in each device can't drive longer cables at high data rates without errors. If your speed is lower or you can find VERY low capacitance cable you may have better results.
If you have an RS422 interface you can easily drive several hundred metres of cable. The best cable type for this is, in order of preference, screened twisted pair, followed by twisted pair. Connect the screen to ground at one end only.
RE: Cable Selection for serial data transfer
regards, -john-
RE: Cable Selection for serial data transfer
Thanks again
RE: Cable Selection for serial data transfer
You can buy packaged RS232 to RS422, and the complementary RS422 to RS 232, signalling converters. These are packaged into a D-type connector to plug straight into the modem or computer sockets resepectively and draw a small amount of power from the RS232 socket. This means that the long cable run in between uses the robust RS422 (differential signalling) standard, but both modem and computer see a normal RS232 connection.
Thay way you get the best of both worlds - high noise immunity without having to modify modem or computer interfaces.
RE: Cable Selection for serial data transfer
Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.