348Digital Trunk ClockingDescriptionThe UNIVERGE SV9100 GCD-CP10 has a built-in clock source for all digital trunk blades. Digital trunkblades are connected via an internal PLO (Phase Locked Oscillator) to derive Primary Clock from thenetwork in priority order. If priority is set up incorrectly, or if two primary clocks are coming in, slips mayoccur causing improper data synchronization. The PLO, equipped with the UNIVERGE SV9100GCD-CP10 is the timing source for all digital trunk blades in the system. The PLO synchronizes thesystem and clocks signals from another office. When the UNIVERGE SV9100 is a clock receiver office,the PLO generates the clock signal according to the source clock signals received from the source officein the network. The source clock signals are extracted from digital trunk blades and are supplied to thePLO.The PLO synchronization source priorities are as follows:1. GCD-PRTA2. GCD-CCTA (External)3. GCD-2BRIA4. GCD-CP10ConditionsIf multiple PRIs exist, the system chooses the first one that synchronized with the carrier.If there are multiple PRIs and the one being used for the source goes down, the systembegins to count forward in slot numbers looking for the next available PRI.If multiple BRIs exist and no GCD-PRTA or GCD-CCTA (External) exists, the SV9100GCD-CP10 chooses the first BRI that synchronized with the carrier.If there is one GCD-PRTA and the one being used for the source goes down, the SV9100GCD-CP10 looks to see if there are any BRIs installed in the system. If there are no BRIs,the SV9100 GCD-CP10 becomes the new synchronization source. The reason for this iswhen a GCD-PRTA is installed in the system, all T1s must be assigned as (INTERNAL). T1(INTERNAL) is not a clocking priority.Default SettingsNoneSystem AvailabilityTerminalsNoneRequired Component(s)GCD-CP10
