NEC NDA-24300 manual Unit Control Block Diagram Dual Configuration

FAULT REPAIR PROCEDURES

4.1 Check Point

When repairing a unit fault, consider the following items:

(1)Speech paths and control paths in the unit are connected to line/trunks via the MUX circuit cards. Be sure to check the alarm lamps on the MUX circuit cards, and check to see if the front cable between each MUX circuit card and TSW circuit card is connected correctly. Figure 5-5and Figure 5-6show the block dia- gram within the unit.

(2)The MUX circuit cards are operating in the ACT/STBY modes under control of the CPU circuit. When the ACT-side CPU has detected a fault in the ACT-side MUX circuit card, CPU changeover is executed and the ACT/STBY mode of the Speech Path System is also changed over. When both of the MUX circuit cards have become faulty, all the lines/trunks in that unit are placed into make-busy state. (If a PFT circuit card is located in that specific unit, the PFT is activated.) Figure 5-7shows the location of the MUX cards.

(3)When both units in a specific PIM are faulty, it is possible that the PWR circuit card mounted in that spe- cific PIM is faulty. In such a case, refer to Section 8, Power Supply Fault.

MUX0	MUX1
Clock	Clock
	(B)
(B)
To	To
TSW/INT	TSW/INT
Speech	Speech
Path	Path
(A)	(A)
Control of	Control of
CPU No. 0	CPU No. 1
ACT/STBY of	ACT/STBY of
CPU No. 0	CPU No. 1
PM	LC/TRK
Line/
Trunk	LC/TRK
Circuit Card
SYMBOLS
: Circuit Card
(A) : Control on ACT/STBY of Speech Path Systems
(B) : Control on ACT/STBY of Clock Systems

Figure 5-5 Unit Control Block Diagram (Dual Configuration)

CHAPTER 5 NDA-24300

Page 334

Issue 1