
22
NON-POWERED INTERFACE CONVERTERS
Table 3-1. Switch Selection
Switch
Function
Possible
Dfn.
Factory
Identity
Positions
Setting
DCD+DSR
SW1
(SW1)
Both signals high.
ON
ON
ON
Both signals
OFF
NC
disconnected.
CTS Status
SW2 SW3 SW4
and RTS to
CTS not provided.
OFF
OFF X
NC
CTS Delay
CTS always high.
ON
OFF X
ON
(SW2, 3, 4)
CTS follows RTS.
OFF
ON
OFF
0 msec
CTS follows RTS.
OFF
ON
ON
20 msec
20 msec
Illegal position!
ON
ON
X
Fault
Do not use!
Carrier
SW5
(SW5)
Carrier controlled
ON
CNTRL
CNTRL
by RTS.
Carrier always ON. OFF
ON
Note: Carrier (SW5) must be in CNTRL position for 2-wire operation.
Receive
SW6
Impedance
Low
ON
120
Ω
(SW6)
High
OFF
12 k
Ω
OFF
Note: For point-to-point connection, the receive impedance should be set to Low. For
multipoint connection, the master and terminating units should be set to Low and all the
other units to High.