DSU Operations5-133610-A2-GB41-70 July 1999Table 5-5Backup Branch Menu SelectionsCurrentDBM ModeMenuSelection EffectIdle BkupDialDial out, establish, and switch to dialed link (Dial Backup mode).Dial out and establish dialed link (Standby mode). The data is routedover the DDS circuit.Standby Disc→DialDisconnect dialed link (Idle mode).Switch data to dialed link (Dial Backup mode).Dial Backup DrBU→DDSDisconnect dialed link and switch to DDS (Idle mode).Switch data to DDS (Standby mode).Aggregate SwitchWhen AggrSwitch (Aggregate Switch) is enabled, thebackup commands have a different effect:• Bkup is used to initiate a point-to-point backup or afull multipoint backup. The DSU disconnects fromthe DDS line and reverts to the timing sourcespecified by the AgSw Timing (Aggregate SwitchTiming) configuration option. Do not initiate thiscommand for a partial multipoint backup.For multipoint applications, data is automaticallybridged to the aggregate port as well as the DDSline when the AggrSwitch configuration option isenabled,• DrBU is used to terminate a point-to-point or fullmultipoint backup. The DSU resumes transmissionon the DDS line. The DSU timing is specified bythe DSU TxClkSource configuration option.The DBM’s mode determines the menu that appearswhen Bckup is selected.With the addition of the TDM or MCMP circuit card,the DCP operation remains unchanged while in Idle modefor the following:• Enabling, disabling, or placing the DBM in DialBackup or Standby mode.• Disconnecting the dial connection, switching datato the dial connection and switching to the DDScircuit.To learn how to enable, disable, or place the DBM inDial Backup or Standby mode while in Idle mode, as wellas how to disconnect the dial connection, switch data tothe dial connection, and switch to the DDS circuit, refer tothe COMSPHERE 3600 Series Data Service Units,Models 3610 and 3611, Dial Backup Module and SNADiagnostic Interface Options, Applications Guide.BridgeWhen the DSU is configured as an extended bridge(EBrdg), the Bckup menu is displayed; however, theDSU-DBM or DSU-DBM-V is always in Dial Backupmode. If an attempt to drop backup (DrBU) is made, aConflict w/Envir message is displayed.When a DSU is configured as a central-site bridge, aDBM circuit card can be installed, but the DBM must bedisabled. When the TDM or MCMP circuit card isinstalled, only two sections are displayed: one turns thebridge ON (Bkup) and the other turns it Off (DrBU).Select Bkup to activate the bridge, disconnect the DDSline from the bridge, and switch to internal timing; selectDrBU to deactivate the bridge; to connect the DDS line tothe bridge and switch to DDS timing.The digital bridge’s mode determines the menu that isdisplayed when Bckup is selected.
