Nortel Networks DCT1900 manual External Sync Cable, To CPU

Technical Product Manual - DCT1900

Installation Instructions, Synchronization Distribution Board (SDB) – REX-BRD0006 or ROANB 101 38

1	2	3	4	1	2	3	4	1	2	3	4
X5				X6				X7

To CPU ---------------------------------------------------------

	X1			A B					X2		A B					X3		A B
To other
CPU	1		2		3	4	5	6	1	2		3	4	5	6	1	2		3	4	5	6
		GND(shield)							GND(shield)							GND(shield)
			SYNC OUT							SYNC OUT							SYNC OUT

1 2 3 4 X8

CIRCUIT GND

CIRCUIT GND

X4	' '
	A B

RJ Connectors

1 2 3 4 5 6

GND(shield)

SYNC IN

Fig. 18–2 Electrical Schematic Diagram

18.2Installation

The SDB comes as part of the installation set sync port kit (NTMNB 101 107) and must be installed in the cabinet where the CPU1 is going to reside (refer to Paragraph 4.7 of Chapter 4). For the installation of the cables to the CPU1 refer to Chapter 19, CPU1 Cabling. The external sync in and out cables are part of the sync port kit and are required if PWT air interface synchronization is needed in a multi DCT1900 system environment. They must meet the requirements in Paragraph

18.3 (see Figure 18-3).

18.3External Sync Cable

When there are multiple DCT1900 systems with overlapping coverage areas it is necessary to synchronize the CPUs of the systems together. This is done by connecting an external sync cable from one of the sync out ports on the master CPU’s sync board to the sync in port on one of the slave CPU’s sync board.

A pre-made external sync cable, TSR 951 284, is available. The specifications for this cable are included below. If this cable is not long enough then a cable must be constructed on site. Refer to the enclosed specifications to construct this cable. If the 6 conductor shielded flat cable is not available then a single pair of 120 ohm twisted shielded pair may be used.

The signal delay in the external sync cable must be determined. For the cable TSR 951 284 it is 0.04μs. A cable made on site must be measured using a TDR (Refer to Paragraph 18.4).

Once the delay is known, this value is entered into the slave system’s CPU during its’ initialization. Refer to the Cordless System Software User’s Guide (LZB 119 2664), Appendix I, on how to enter this delay.

18-2	Install-DCT1900/R8/mw
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