RS232 vs RS422

[peter ho]

Can someone help me with the RS422 programing? I have a device that can be controlled via RS232 or RS422. I can write a program to control this device in RS232 mode. My question is, does this program still work if I switch the device to RS422 mode? What do I need to do to make this program work in RS422 mode? Do I need a RS232 - RS422 converter? thanks,peter.

[Tim Smith]

Yes, you would need a RS232-RS422 converter. Other than that, you won't have to change your software. Except... I can never remember if it is the RS422 or the RS485 converter that might use a control signal to know when it send or receive data. Your flow control settings should hand this without problem (CTS/RTS or DSR/DTR). However, this is usually important only for multi-drop system. If you want your RS232 application to support RS422 and RS485, just make sure you support both your hardware flow control settings. In 8 years of process control with our product, we have never run into a RS422 or RS485 issue. FYI: For distance applications or high noise, RS422 is much better. You will find it commonly used in any type of hostile environment. Tim Smith I'm going to patent thought. I have yet to see any prior art.