NEC ND-71762(E) Receiver Office and Local Receiver Office, shows the routes for clock extraction

GENERAL INFORMATION FOR CCIS

5.2.3Receiver Office and Local Receiver Office

For connecting the DTI (Digital Trunk Interface) of the user office to the DTI of a higher-ranking office, the user office must establish clock synchronization with the higher-ranking office concerned.

A Receiver Office or a Local Receiver Office extracts carrier clocks (24DTI: 1.544 MHz/30DTI: 2.048 MHz) from the DTI opposing to the higher-ranking office and establishes clock synchronization with the higher-ranking office by supplying the extracted carrier clocks to the PLO/TSW (Subordinate oscillator) in the user office.

Figure 2-13 shows the routes for clock extraction.

Figure 2-13 Routes for Extracted Clocks

This figure shows an example of the clock supply routes when PLO0/TSW0 is in ACT side.

Clock receiving route

(max. 4 routes)

From DTI

PLO 0

(PH-CK16)

/TSW 0

(PH-SW10)

Two systems each

ACT

32.768 MHz

8 kHz (FH)

To Switch System side

ACT CLOCK

Change Synchronization

PLO 1

(PH-CK16)

/TSW 1

(PH-SW10)

Note: The TSW (PH-SW10) card is used for the 1-IMG system only. The PLO (PH-CK16) card is used for the 4-IMG system.

CHAPTER 2 ND-71762 (E)

Page 18

Issue 2