S
WITCH
1: N
OT
U
SED
S
WITCH
2: C
ARRIER
E
NABLE
Use switch 2 to specify how the carrier signal is raised.
In most point-to-point, full-duplex applications, the
carrier signal can remain constantly “high.” In a
multipoint environment, contention for the line is
controlled by RTS.
Switch 2
Setting
On
Constant carrier (Default)
Off
Controlled by RTS
S
WITCHES
3
AND
4: T
RANSMIT
C
LOCK
Use switches 3 and 4 together to specify the clocking
method. The SHM-NPR can provide an internal clock
(pin 15), receive an external clock (from pin 24), or
loop back a receive clock.
Switch 3
Switch 4
Setting
On
On
External clock
On
Off
External clock
Off
On
Internal clock (Default)
Off
Off Receive loopback
13
CHAPTER 3: Configuration
