
RS-232/RS-422/485 Option 21
Half Duplex RS-422/485
By jumpering positions A and C of jumper blocks JB4, JB5, JB6
and JB7 you can run the individual RS-422/485 ports in half
duplex mode. In this mode your Xtreme/104 Opto adapter
controls the transmitter and receiver circuits. RTS is turned on
prior to and during transmission to cause the transmit driver to
enable and the receiver to disable. RTS is turned off when not
transmitting to cause the transmit driver to disable (tri-stated) and
the receiver to enable. The Xtreme/104 Opto adapter is
responsible for timing the RTS toggle.
Figures 1 and 2 show the locations of jumper block JB4, JB5,
JB6, JB7 and J1, J2.
Example
The example below shows the settings on JB4, JB5, JB6, JB7 and J1,
J2 where RS-422/485 ports 1, 2 are set for half duplex mode. Ports 3,
4 are RS-232 and therefore should not be set for half duplex.
JB4
JB5
JB6
JB7
J1
Jumper is
on J1
J2
Jumper is
off J2
A
B
C
D
E
F
G
H
I
A
B
C
D
E
F
G
H
I
A
B
C
D
E
F
G
H
I
A
B
C
D
E
F
G
H
I
Note: Rev A & B Xtreme/104 Opto adapters do not have
positions H & I on jumper blocks, JB4, JB5, JB6, and JB7
Jumper Legend
(Rev. C & later adapters)
A = TxD control
B = RS-232/RS-422/485 select
C = RxD control
D = RTS terminator
E = TxD terminator
F = RxD terminator & bias
G = RxD terminator & bias
H = CTS terminator & bias
I = CTS terminator & bias
Jumper Legend
(Rev. A & B adapters)
A = TxD control
B = RS-232/RS-422/485 select
C = RxD control
D = RTS terminator
E = TxD terminator
F = CTS terminator
G = RxD terminator
Technical Tip:
J1 controls ports 1 and 2 and J2 controls ports 3 and 4. If both ports
1 and 2 are set for full duplex then J1 should not be jumpered. If both
ports 3 and 4 are set for full duplex then J2 should not be jumpered.
Xtreme/104 Opto User's Manual, ver. 0.03
Kommentare zu diesen Handbüchern