A. Jumper Configurations
115
W28-31
RS-485 Transmitter Configuration - independently configures the transmitter input
source and transmitter enable for the RS-485 channels. 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.
W28a
W28b
COM1 Transmit Enable
†
IN
OUT
COM1 DTR
OUT
IN
COM1 TXD (J1708)
OUT
OUT
Enabled
W29a
W29b
COM1 Transmit Input
†
IN
OUT
COM1 TXD
OUT
IN
Logical 0 (J1708)
W30a
W30b
COM2 Transmit Enable
†
IN
OUT
COM2 DTR
OUT
IN
COM2 TXD (J1708)
OUT
OUT
Enabled
W31a
W31b
COM2 Transmit Input
†
IN
OUT
COM2 TXD
OUT
IN
Logical 0 (J1708)
†
Factory default configuration for DOS systems.