ProSoft Technology MVI56E-GSC/ GSCXT - Manual (Page 136)

Reference MVI56E-GSC ♦ CompactLogix or MicroLogix Platform
User Manual Enhanced Generic ASCII Serial Communication Module
Page 136 of 140 ProSoft Technology, Inc.
May 9, 2014
Note: Terminating resistors are generally not required on the RS-485 network, unless you are
experiencing communication problems that can be attributed to signal echoes or reflections. In
these cases, installing a 120-ohm terminating resistor between pins 1 and 8 on the module
connector end of the RS-485 line may improve communication quality.
RS-485 and RS-422 Tip
If communication in the RS-422 or RS-485 mode does not work at first, despite
all attempts, try switching termination polarities. Some manufacturers interpret +
and -, or A and B, polarities differently.
4.10.7 DB9 to RJ45 Adaptor (Cable 14)