SEP 2005 MODEL 1000
INSTALLATION AND SETUP
3-56
CPU COM4 RS-422 Configuration
RS-422 signal levels are supported on any, or all serial channels, with the installation of the optional
"Chip Kit" (P/N 3-2350-115). This kit provides the driver ICs necessary for a single channel of
RS-422. If two channels of RS-422 are required then two kits will be needed. RS-422 is a 4-wire,
point-to-point full-duplex interface allowing much longer cable runs than are possible than with
RS-232. The differential transmitter and receiver twisted-pairs offer a higher degree of noise
immunity. The following illustrations show the correct jumpering, driver IC installation and I/O
connector pin definitions for each of the COM4 channels when used in RS-422 mode.
Figure 3-17. COM4 RS-422