How do you make a rs 232 to 485 cable

Question

How do you make a rs 232 to 485 cable

Answer 1

RS 232 and RS485 communications systems cannot be connected by simply adapting a cable between them.  An active electronic converter is required to change between the signals.

RS-232 uses a single-ended voltage signal referenced to the ground wire, so Transmit and Receive wires are both referred to Ground.  

RS-485 use a differential voltage between the two signal wires A & B.  

Note that RS-485 is defined as a multi-point protocol, while RS-232 is strictly point-to-point.  So, the RS-485 line drivers have to go into a high-impedance state when they are not transmitting or receiving, to allow other devices to use the line.  RS-232 does not require this.

Look for converters at B&B Electronics, Black Box, and plenty of other places around the net.  They are common in industrial communications.

Answer 2

You can use a PolyCom I converter to convert to the above specifications, here are the instructions: http://www.action-electronics.com/amkor....

You can use other converters/adapters as well, check out these links:

http://www.rs485.com/pconverters.html

http://www.antona.com/dta6085.htm

http://www.rs232-converters.com/

http://www.usconverters.com/index.php?ma...

http://www.moxa.com/land/Serial_to_Fiber...