NEC ND-71762(E) system manual Digital Network and Network Synchronization 5.1 Outline

GENERAL INFORMATION FOR CCIS

5.DIGITAL NETWORK AND NETWORK SYNCHRONIZATION 5.1 Outline

To set up a digital network, it is necessary to establish clock level synchronization among the offices composing the network.

Among various kinds of synchronizing methods, the PBX is using Receiver synchronization as the standard method. As for the office ranks, there are the following four kinds:

•Source Office

•Sub-Source Office

•Receiver Office

•Local Receiver Office

Refer to Table 2-3 for synchronization method at network-level.

For types of PBX applicable for each office hierarchy, refer to Table 2-4.

Table 2-3 Office Ranks and Kind of Oscillator

	OSC	M-OSC	EXT. OSC	PLO/OSC	PLO/TSW	REMARKS
OFFICE RANK		(Note 2)	(Note 1)	(High Precision Oscillator)	(Subordinate Oscillator)
Source Office		⋅	—	—	—
Sub-Source Office		—	⋅	⋅	—
Receiver office		—	—	⋅	⋅
Local Receiver Office		—	—	—	⋅
⋅: Applicable	—: Not Applicable
The clock precision is as follows.
M-OSC = EXT. OSC = High precision - PLO/OSC = Subordinate - PLO/TSW
>	>			>

Note 1: M-OSC (Master Oscillator) and EXT. OSC (External Oscillator <for back up>) is not to be furnished by NEC.

Note 2: High Precision Oscillator - PLO (PH-CK17) / OSC (PA-CK14)

Subordinate Oscillator - PLO (PH-CK16) / TSW (PH-SW10)

For the 1-IMG system, the OSC/TSW card is used in place of PLO.

CHAPTER 2 ND-71762 (E)

Page 14

Issue 2