LI2Y(St)CY PIMF (RS 232 - RS 422)

Instrumentation and Control Engineering
Industrial Electronics
Computers and Office Machines

NOTES

RS-232: it is a well-known interface standard. It is designed for serial data exchange between two devices. Data can be transmitted 15 ~ 31 meters by a suitable cable. It allows data transmission up to 20Kbps RS 422: It is as a two serial communication standard and more correctly named as EIA/TIA-422. Communication systems based on RS-422 communicate digital information over twisted pair wire from transmitters to receivers. Devices can be apart from each other up to 1220 meter without any repeaters and RS 422 drivers can tranmit to up to 10 receivers (1 driver 10 receivers) and RS 422 systems can communicate at rate from 100Kbps (at 1200 m) up to 10Mbps (at 12 m) varing by cable length. This systems utilize balanced outputs and differential inputs. As a result, they provide better noise immunity than single-ended systems such as RS 232. Thus links using RS 422 operate over longer distance at higher speed than links using RS 232. RS 422 also makes it possible to create point-to-multipoint connections but RS-485 devices are required for master to receive data back from each slave.