NEC NEAX2400 ICS, Руководство по программированию

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NEAX2400 IPX Feature Programming Manual
NDA-24297, Issue 1
Page 293
Direct Digital Interface D-16
Service Conditions (cont’d)
b.) Sub-Source Office: This office operates using a Phase Lock Oscillator (PLO) to synchronize with
the clock at the Source Office. If the Source Clock has some failure, office can operate using its
own backup oscillator.
c.) Receiver Office: This office is arranged so it will have at least two clock routes, one for Receiver
and the other for standby. Synchronization Clock is derived from incoming PCM bit stream from
higher hierarchy offices.
d.) Local Receiver Office: This is the end office in a digital network arrangement. This office will
not be provided with a backup route for the PLO, because this office is the only one influenced in
an event of trouble occurrence.
6. Each NEAX2400 IPX can be equipped with a duplicate Phase Lock Oscillator used for network
synchronization. Each PLO has 4 inputs to which clocks from the Source Oscillator or Digital Interface
Module should be connected.
Network Clocking Hierarchy
S: Source Office
SS: Sub-Source Office
R: Receiver Office
LR: Local Receiver Office
Direction of Clock
S
SS SS
R R
LR LR LR