Connect Tech Xtreme 104 Opto, User Manual

Page: 27 / 32

RS-232/RS-485/422 Option 21
Xtreme/104 User's Manual, ver. 0.01
Half Duplex RS-485
By jumpering positions A and C of jumper blocks JB4, JB5, JB6
and JB7 you can run the individual RS-485/422 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
Figure 1 shows the locations of jumper block JB4, JB5, JB6, JB7
and J1, J2.
Example
The example below shows the settings on JB4, JB5, JB6, and
J1, J2 where RS-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
A
JB5
B
C
D
E
F
G
A
B
C
D
E
F
G
JB6
A
B
C
D
E
F
G
JB7
A
B
C
D
E
F
G
J1
Jumper is
on J1
J2
Jumper is
off J2
Technical Note:
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.