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CHAPTER 5 Operation Procedure for System with PIR
4.4.3 Unit Fault - Fault Related to Speech
Faulty Situation:
• Noise, one-way speech, no tone, etc. occurs only within a unit.
• Even if dialing has started, dial tone does not stop.
Note: Exchange the TSW circuit card when MUX is not mounted on PIR.
<<For Dual Configuration>>
(1) Check by replacing the MUX circuit card.
• After replacement of the MUX circuit card, make a station-to-station call in the faulty unit and see if
speech is normal.
(a) Replace the MUX circuit card referring to Section 1.5, Replacement Procedure of MUX (Multiplexer)
Circuit Card.
(b) Place the MUX circuit card into ACT mode referring to How to Control Switching Block in Chapter 2.
(2) Check by replacing the TSW circuit card.
• After replacement of the TSW circuit card, make a station-to-station call in the faulty unit and see if
speech is normal.
(a) Place the TSW circuit card into ACT mode referring to How to Control Switching Block in Chapter 2.
(3) Check the line/trunk circuit cards mounted in the unit to see if they are faulty.
(a) Set the MB switch of the line/trunk circuit card UP and extract it from its mounting slot.
(b) Make a station-to-station call and see if a fault occurs.
(4) Perform this check on an individual basis.
(a) If the fault has stopped occurring, the circuit card extracted at that time is faulty. Replace the circuit
card with a spare.
(b) If the fault continues, check the next circuit card.
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