User Guide

Configuration Option Tables
A-3
7610-A2-GB20-10
November 1997
Table A-1. System Options (2 of 3)
DDS Line Rate (Kbps)
Possible Settings: 56, 64CC, Autobaud
Default Setting: Autobaud
The unit starts up with Autobaud. When the DDS line rate obtained from the service
provider is detected, Autobaud is replaced with the actual rate.
 DDS Line Rate (Kbps) option appears when Operating Mode is set to DDS.
NOTES: – Setting the actual data rate results in minimum power-up time. (If both
DSUs use Autobaud, the process can take several minutes.) Configure
the actual data rate after initial installation.
– The clock rates generated by the DSU at the DTE interface (TXC and
RXC) equal the operating rate minus the configured rate of 1600, 4000,
or 8000 bps for the IMC, if enabled. Refer to the In-Band Management
Channel Rate (bps) option in Table A-2.
56 – 56 kbps line rate.
64CC – 64 kbps Clear Channel on a 72 kbps circuit.
Autobaud – This setting is automatically changed to the actual operating line rate of
56 kbps or 64CC as soon as the signal is detected.
LADS Timing
Possible Settings: Internal, External, Receive
Default Setting: Internal
Determines the timing source for the unit.
 LADS Timing option appears when Operating Mode is set to LADS.
Internal – Timing derived from the unit’s local clock. Use this setting for the LADS
primary timing unit that establishes the timing for both point-to-point units.
External – Timing is derived from the external clock provided by the DTE connected to
the V.35 interface on circuit CT113 (pins U, W).
NOTE: The valid rate generated by the DTE must be equal to the LADS line rate
minus the configured rate of 1600, 4000, or 8000 bps for the IMC, if
enabled. Refer to the In-Band Management Channel Rate (bps) option in
Table A-2.
Receive – Timing is derived from the line receive signal unless the unit is running
diagnostic tests. During the tests, the timing source is the internal clock. This setting
should be used for a LADS secondary timing unit.
LADS Line Rate (Kbps)
Possible Settings: 56, 64
Default Setting: 64
Line operating rate for LADS operation.
 LADS Line Rate (Kbps) option appears when Operating Mode is set to LADS.
56 – 56 kbps line rate. Provides increased distance for the LADS applications.
64 – 64 kbps line rate.