Switches S2-4 and S2-5: Clock Mode
Use Switches S2-4 and S2-5 to set the source of Model 2530’s
transmit clock.
S2-4
S2-5
Clock Mode
Description
Off
On
External (DTE)
Transmit clock derived
from terminal interface
Off
Off
Network (Looped)
Transmit clock derived
from the received line
signal; Use this mode
for Dedicated DDS
operation
On
On
Internal (Master)
Transmit clock derived
internally
On
Off
Campus Clock
Transmit clock derived
from the received line
signal. Allows remote
device (in
campus
clock mode) to initiate
V.54 loopback. For use
only in campus short-
haul configuration.
(Note: Local device must
be set in
internal clock
mode.)
Switch S2-6: Force RTS
Use S2-6 to force the transmitter ON, thereby ignoring the DTE’s
RTS signal. In the Off position, RTS controls the transmitter by forcing
it to send either the DTE data or an idle pattern.
S2-6
RTS
Description
On
Forced On
Transmitter is always ON
Off
Follows
The RTS input controls the
DTE Signal
transmitter
NOTE: At 64 kbps Force RTS is always on.
9
Switch S2-7: Data Set Ready During LOCAL Loopback Test
Use Switch S2-7 to control the behavior of the DSR signal at the
DTE interface during the local loopback test.
S-3
Setting
On
DSR is on during local line loop
Off
DSR is off during local line loop
Switch S2-8: Circuit Assurance
On dedicated circuits, the transmitter and the CTS output can be
configured to go ON only when a working communication circuit is
established. If Circuit Assurance is used, enable it on only one end of
the communication link. Use Switch S2-8 to configure circuit assur-
ance.
Circuit
S2-8
Assurance
Description
On
Enabled
CTS will go low and the
transmitter will be held off if the
receiver is in the No Signal state
or CD is low
Off
Disabled
The transmitter and CTS will
operate without regard to the
receiver state
10
Important: For X.21 or Async cam-
pus short haul modem applications,
please configure one Model 2530 for
internal clock mode and the other
Model 2530 for receive recover clock
mode.
