Recovering Clock from PSTN Line Interface

This section provides a brief description for configuring synchronization based on recovering clock from the PSTN line interface. For a full description of the clock parameters, see PSTN Parameters.

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To configure synchronization based on clock from PSTN line:

1.

Open the TDM Bus Settings page (Setup menu > Signaling & Media tab > Gateway folder > TDM Bus Settings).

a.

From the 'TDM Bus Clock Source' drop-down list (TDMBusClockSource), select Network to recover the clock from the line interface.

b.

In the 'TDM Bus Local Reference' field (TDMBusLocalReference), enter the trunk from which the clock is derived.

c.

Enable automatic switchover to the next available "slave" trunk if the device detects that the local-reference trunk is no longer capable of supplying the clock to the system:

i.

From the 'TDM Bus PSTN Auto FallBack Clock' drop-down list (TDMBusPSTNAutoClockEnable), select Enable.

ii.

From the 'TDM Bus PSTN Auto Clock Reverting' drop-down list (TDMBusPSTNAutoClockRevertingEnable), select Enable to enable the device to switch back to a previous trunk that returns to service if it has higher switchover priority.

iii.

In the Trunk Settings page (see Configuring Trunk Settings), configure the priority level of the trunk for taking over as a local-reference trunk, using the 'Auto Clock Trunk Priority' parameter (AutoClockTrunkPriority). A value of 100 means that it never uses the trunk as local reference.

2.

(E1/T1 Trunks Only) Configure the PSTN trunk to recover/derive clock from/to the remote side of the PSTN trunk (i.e. clock slave or clock master): In the Trunk Settings page, configure the 'Clock Master' parameter (ClockMaster) to one of the following:

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Recovered - to recover clock (i.e. slave)

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Generated - to transmit clock (i.e. master)