NEC nd-20292 manual Test system using default program

ND-20292

CHAPTER 5

APRIL, 1990

Intermittent Ring Problems

ICheck memory block 16 to

ensure line is programmed to ring on an existing station

No

v

Program ring

Assignment and

test

11End

Run the following tests:

1.Measure CO ring voltage with AC meter (100 vat 2OHz) at the MDF.

2.Perform a second initialization.

3.Place an external ringer in front of the system on a worst case CO line. Find

out if the customer can

hearthe external ringer at times when the system

does not detect ringing on this line.

4.Replace TSW-E and

test. If problem is not

solved,	perform	1 st
initialization,		replace	CPU-

E ( ). Test system using default program.

AlITerminalsTestto a:see if problem. occurs on all Multiline

assigned ringing

7

Replace at least one Multiline

1 Terminal whicihas problems. 1

and deny the DND feature.

v+No+7

I

Check tosee if lines

affected can be isolated to one COLE ETU

Reset COI-E( ) ETU and test.

Replace COI-E( ) ETU

Check to see if lines

affected can be isolated to one module

Reset MMC-E ETU and test. 1 .../ Replace MMC-E ETU.

Reset TSW-E ETU and test. Replace TSW-E ETU.

500 -10