TN793 PROBLEM!!!!

[TELECOMSONATRACH]

Hi;
we have an Avaya S8720 server, we manage this system for more than eight years.
the number of users available equipped analog stations is 500phones; at the start everything works but since two years some stations begins to stop working increasingly, we are in a critical situation and it remains annoying work just 200phone!!! used cards are TN793.. it is useless to buy other analog card and we don't know what exactly is the problem, possible that these cards will be damaged in their turn?
please we need help

 

[telecomadmin12]

You would have to tell us more about what is exactly happening with these phones. From the amount of information you are providing it is difficult to give advice.
E.g.,do calls drop? No dial tone when you pick up the phone? Always the same phones out or only the ones on certain TN793 cards?

There are a lot of things that could be wrong here.

 

[TELECOMSONATRACH]

the problem persists this way: Phones starts making a noise and after we hear anything, I replaced these cards damaged by good cards but the 24 connected phones with little temp connected phone begins to stop so the card stops functioning ,
same I completely change the slot but no answer
I lost several cards

 

[TELECOMSONATRACH]

and even the phone voltage is less than 48v

 

[TELECOMSONATRACH]

any Ideas??

 

[jimbojimbo]

There are a variety of reasons. Are the phones in a single building or distributed across multiple buildings? If distributed are you exceeding the wire distance? Do you have the correct wiring, protectors, and grounding? Have you measured NEXT? Is the wiring running parallel to an inductive force?

The TN793 is very reliable. Are you using a TN793, TN793B, or TN793CP? What country are you in?

 

[TELECOMSONATRACH]

we are from Algeria;
we use TN793CP, the phones are distributed on multiple buildings and the distance does not exceed 1km.
what do you mean by measured NEXT?
the wiring running is parallel to an inductive force of course with the electric power cable.

 

[dialtonebone]

NEXT = Near End Cross Talk

 

[TELECOMSONATRACH]

How can I measure this parameter?
and if it will serve me to solve this problem?