Principles of Operation
4-173610-A2-GB41-60 March 1999
•Case 2 – V.32 Backup for high-speed DSU
(Figure 4-12). The DBM port speeds must be
reconfigured so that their sum is less than or equal
to 14.4 kbps, the PSTN line speed. When the sum
equals the line speed (now 14.4 kbps), one of the
synchronous ports must be configured for
underspeed.
One possible configuration is to allow one port to
remain at 9600 bps, reconfigure one port to
4800 bps running at underspeed, and reconfigure all
other ports to Off.
An alternate configuration that retains all ports is to
configure two ports at 2400 bps and two ports at
4800 bps, with one of the ports set to Underspeed.
The backup port speeds can be reallocated to match
your circuit priorities.
Figure 4-12. Case 2 – V.32 Backup for High-Speed DSU