Omega Four Port RS-232/422/485 to USB Adaptor Manuale Utente
Configuration
OMG-USB-SER-4
Page 5
Switch Descriptions
Figure 1: Switches SW2 and SW4
L
485 option, OFF for 422.
OFF:
OFF:
No effect
ON :
Connects TX+ to RX+ for two-wire operation
L
485 option, OFF for 422.
OFF:
OFF:
No effect
ON :
Connects TX- to RX- for two-wire operation
PU
485 option, OFF for 422.
OFF:
OFF:
No effect
ON :
Adds a 1 K ohm pull-up resistor to RX+
PD
485 option, OFF for 422.
OFF:
OFF:
No effect
ON :
Adds a 1 K ohm pull-down resistor to RX-
T
422 and 485 option.
OFF:
OFF:
No effect
ON :
Adds a 120 ohm termination resistor between RX+ and RX-
ON
1
2
3
4
5
6
7
8
2
3
4
5
6
7
8
OFF
9
10
10
Port 3
L
L
T
P U
P D
L
L
T
P U
P D
Port 4
L
L
T
PU
PD
L
L
T
PU
PD
SW2
Port 1
L
L
T
PU
PD
L
L
T
PU
PD
ON
1
2
3
4
5
6
7
2
3
4
5
6
7
8
OFF
9
10
10
Port 2
L
L
T
PU
PD
L
L
T
PU
PD
SW4