COMSPHERE 3600 Series Data Service Units
4-18 March 1999 3610-A2-GB41-60
•Case 3 – V.32 Backup for high-speed DSU with
extended circuits (Figure 4-13). When the
backbone circuit is restored at 14.4 kbps, the port
speeds at the tributary DSU may need to be
reduced. If the port speed of the extended circuit
must be reduced, then the speed of the extended
modems must be reduced accordingly. The
speed-selection feature of the TDM circuit card will
provide this function to modems (such as the
COMSPHERE 3400 Series modems) that are
capable of falling back in speed in response to an
Off signal on their speed-select input lead. This
requires a special crossover cable (feature
number 3400-F1-501).
Figure 4-13. Case 3 – V.32 Backup for DSU with Extended Circuits