Printed in the Federal Republic of Germany
TR-Electronic GmbH 2018, All Rights Reserved
03/19/2021
TR-ECE-BA-DGB-0141 v03
Page 45 of 67
4.2 RS422 Data transmission technology
At the Signal transmission one line-pair is used for the signals Data+ and Data
– and
one line-pair for the signals Clock+ and Clock
–.
The serial data are transmitted without mass reference as a voltage difference
between two corresponding lines.
The receiver evaluates only the difference between the two lines. Therefore common-
mode interferences on the transmission line do not lead to a corruption of the useful
signal.
By the use of shielded and twisted pair cable, data transmissions over distances from
up to 500 meters with a frequency of 100 kHz can be realized.
Under load RS422 transmitters provide output levels of ± 2 V between the two
outputs. The receivers still recognize levels of ± 200 mV as valid signal, but this does
not apply to an input circuit with opto coupler.
