UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE

2.3.4PLO Card Replacement Procedure

The PLO (PH-CK16/17/16-A/17-A) card is located in Slot No. 21 or 23 within the TSWM. Used to- gether with a different direct digital interface circuit card, the card’s main function is to set up the clock synchronization on the network. In addition, the MUSIC ROM supplies the hold tone to each station line via the TSW circuit card. Use the procedures below to replace the PLO card with a spare.

Note: The ACT/STBY of PLO can be changed over via a single MB key operation on the circuit card. Though its circuit is controlled by the GT (PH-GT09) card via TSW I/O bus, the switching system of PLO is not affected by the speech path system changeover, differing from other echelons such as TSW, MUX, DLKC. Refer to Section 12, System Control Procedures, in Chapter 6.

Replacement Procedure

START

On the PLO (PH-CK16/17/16-A/17-A) card to be replaced, set the MB key UP.

Check the mate PLO's ACT mode.

Extract the PLO card to be replaced from the TSWM.

ATTENTION

Contents

Static Sensitive

Handling

Precautions Required

PLO system is changed over from ACT to STBY mode.

OPE lamp on the PLO card goes

OFF.

Check the mate PLO card's following lamp indication:

• OPE = Steady-green

Set the keys on the new card according to the card replaced.

A

NDA-24300CHAPTER 4

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NEC NDA-24300 manual PLO Card Replacement Procedure, Off