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XymphonyProgramming-SystemSynchronization

The synchronization algorithms in Telesis systems provide two basic modes of synchronization - with external synchronization source and with internal clock.

In case of external synchronization source, input for reference clock is signal with 2048 kHz and, amplitude and impedance according to ITU-T Rec. G.703, that is E1 interface.

The Telesis system may be programmed such that;

• It may be the master (uses its own internal clock), or
• It may be a slave and tries to synchronize an external clock from one or more E1s

and if it fails (master clock is not available), it passes to the free running mode.

In order to select the synchronization source, click on Basic link in Homepage.

Then, Basic System settings page opens.

Select a source interface such that the system would extract the clock (synchronization) information form Digital trunks for sync. pulldown list. Available options may depend on the system model or type, and existing E1 interfaces.

Some possible ones are:

• Free Running: The system would generate its own clock, there would not be clock extraction from another source.
• 0: The system would extract the clock from the E1 with factory default access code(s) 50000 (for CCS signaling) or (50001 to 50031 for CAS signaling). If it can not do this (due to loss of signal etc.), then the localy generated system clock is used (that is free running mode).
• 1: The system would extract the clock from one of the two E1s, these are
  • E1 with factory default access code(s) 50100 (for CCS signaling) or (50101 to 50131 for CAS signaling), and
  • E1 with factory default access code(s) 50000 (for CCS signaling) or (50001 to 50031 for CAS signaling).
• 2: The system would extract the clock from one of the three E1s, these are:
  • E1 with factory default access code(s) 50200 (for CCS signaling) or (50201 to 50231 for CAS signaling), and
  • E1 with factory default access code(s) 50100 (for CCS signaling) or (50101 to 50131 for CAS signaling), and
  • E1 with factory default access code(s) 50000 (for CCS signaling) or (50001 to 50031 for CAS signaling).
• and so on.

Due to the above mentioned selection algorithm, it is always necessary to use the lowest hardware addressed E1s to connect to network, where the system would synchronize. To illustrate, in a Telesis system with SS7 and ISDN Signaling E1 interfaces, it is almost certain that the Telesis system would need to be in synchronous with the SS7 network. So that, the lowest hardware addressed E1s should be programmed for SS7 signaling, connected to the SS7 network and Digital trunks for sync. should be set for these E1s.

During the operation of the system, Current synchronization source row displays the E1 interface where the system is synchronized (or Free running).