COMSPHERE 3600 Series Data Service Units
D-4 March 1999 3610-A2-GB41-60
TDM Scenario 2 – Using Switched 56 kbpsDial Backup
In this configuration, shown in Figure D-2, the
Switched 56 DBMs provide the capability for full backup
of a TDM circuit operating at 56 kbps. (If the DDS circuit
operates at less than 56 kbps, the Switched 56 DBM uses
rate adaption to match the DDS speed.)
For this scenario, the DSU supports three applications
running at 4.8 kbps, 9.6 kbps, and 19.2 kbps. During dial
backup, the ports can be set to the same speed since the
DSU rate is the same as the DBM rate.
In this example, dial backup is configured for
automatic dial backup and automatic restoration for both
the control and the tributary, and LPDA-2 is enabled.
Make sure that you enter at least 2 minutes difference
between the control’s Network Time-Out (NtwkTimOut)
configuration option and the tributary’s.
Configuration Options
For TDM scenario 2, use the Configuration Worksheet
for TDM Mode and set the configuration options that
follow for both the control and tributary DSUs.
•MUX – Setup
MUX Funct: TDM
Share DevA: Disab
Share DevB: Disab
P1/2 FEPSh: Disab
P3/4 FEPSh: Disab
P5/6 FEPSh: Disab
•Prt1, Prt2, and Prt3 (Prt4 through Prt6 N/A)
Async→Sync: Disab
TxCarrSel: Const
RxCarrSel: Const
Elast Stor: Disab
RTS/CTS Del: 0
AntiStream: Disab
•PrtSp – DSU
Prt1: 4.8
Prt2: 9.6
Prt3: 19.2
Prt4 through Prt6: Disab
Figure D-2. TDM Configuration: Scenario 2 – Switched 56 kbps Dial Backup