A. Jumper Configurations
112
W12-15
RS-485 Duplex Selection - independently selects half duplex or full duplex for each RS-
485 channel. The COM1 and COM2 serial ports are software configured for RS-232 or
RS-485 operation through
System Register 2
. If configured for RS-485, the following
jumpers adjust the RS-485 architecture to a specific application. These jumpers do not
apply to the ZT 8903.
W12
W13
COM1 Duplex
†
IN
IN
Half duplex (two wire)
OUT
OUT
Full Duplex (four wire)
W14
W15
COM2 Duplex
†
IN
IN
Half Duplex (two wire)
OUT
OUT
Full Duplex (four wire)
W16
CMOS RAM Erase - removes the contents of the battery-backed CMOS configuration
RAM. The CMOS RAM is erased by turning off the power and moving the W16a
shorting jumper to position W16b and back to W16a again.
W16a
W16b
CMOS Configuration RAM
†
IN
OUT
Normal operation
OUT
IN
Erase
†
Factory default configuration for DOS systems.