Talk to a Sewell Support Expert

RS232/RS422/RS485 -What are the differences?

This serial interface is the most common serial interface. It uses a 2 wire system to communicate. Most serial devices are compatible with this interface, and most older computers come with this port. However, this interface does have its weaknesses:

-It can only send a signal up to 50ft without any active serial extensions.
-It is limited in its data transfer speed(20kb/s).
-Since its transmit and receive lines are linked through the same ground(single-ended referenced) it tends to pick up noise.
-Only one device can connect to the port at a time(there are some rare exceptions).

RS422 does have its advantages to RS232, it also has its disadvantages. RS422 is not supported by as many devices as RS232. It also has a lot of advantages over RS232. Its main difference is that it uses 4 wires to communicate rather than 2. Some of it’s specs are as follows:

-Can support up to 32 devices on one port, through multiple switches
-Can transfer data at a higher speed than RS232(10Mb/s-100Kb/s).
-Can extend longer distances than RS232(from 500 to 4000 ft).
-It has a differential reference for its transmit and receive lines(less noise).

RS-485 has even more commonalitites with RS422 than RS232. They both support up to 32 devices, and they both have the same data transfer rate(10Mb/s-100Kb/s) and can be extended to the same length(from 500 to 4000 ft). RS485 does use less cables than RS422 since it is a 2 wire system, reducing clutter. However, RS485 is more difficult to program than RS422.

BBB Certified We accept Visa, Mastercard, American Express, DiscoverCard, Paypal, and Google Checkout

Great service, fast delivery, low shipping rates.
Copyright © 2010 SewellSupport.com