FAULT REPAIR PROCEDURES

ATTENTION

Contents

Static Sensitive

Handling

Precautions Required

If the TLT is a 2W E & M System, connect the related leads as shown below:

TLT

T T

R R

E E

M M

TLT

(3) For a DTI

A

LC

D T I

B

LC

D T I

Set up a loop-back connection between the DTI Trunk to be tested and another DTI Trunk as shown below:

DTI

Receive

Send

R R

R R

T T

T T

Receive

Send

DTI

If the office is the PLO-source office, perform the tests by disconnecting the PLO and M-OSC. The mode of the PLO becomes Self Operation Mode.

When the loop-back test is performed at the time of PCM LOSS, FRM LOSS, or MERM LOSS alarm lamp (red) illuminates. If the alarm lamp goes out, the DTI circuit card side is normal.

When only one DTI circuit card is to be checked, make the following connections and confirm that no alarm lamps illuminates.

DTI

Receive

Send

RA RB

TA TB

Loop-back

Cross Connection

CHAPTER 5

NDA-24300

Page 328

Issue 1

Page 355
Image 355
NEC NDA-24300 manual Ra Rb Ta Tb