Loopstart trunk problem

[MetlePro]

Hello all,

Here's the situation. We have this Option11c rel.23.55 running with numerous loopstart trunks.
We have a problem with one of the trunks not getting enough ringing voltage for the callpilot to pickup when he's on any port of the trunk cards.
When you remove him from the pbx, he gets the normal voltage for ringing( no problem then ).
As soon as you put em back on the pbx there seems to drop the ringing voltage.
- This problem only exists with 1 line
- This problem exists on every port you put the cable on
- The CO can only provide Loopstart Trunks

My question is, what can be the cause of the problem? The CO allready came by to check the voltages, and has determined that the correct voltage is supplied and that the fault is at the pbx....


Pro reffers to my company, not my status

 

[TAnselm]

Check for a ground fault that could be sapping voltage.

 

[MetlePro]

Hi TAnselm,

If that would be the case, what grounding would need checking? Is it the grounding of the PBX itself?

Pro reffers to my company, not my status

 

[johnpoole]

with the line open between the co and your trunk port check each side to ground.. needs to be infinite resistance.. i've also seen week protection modules cause that..

something is loading that ckt.. have you determined that it is not the trunk card?

what provider can not provide ground start trunks? that has been default pbx and co to co trunks for 50 years.. prior to t1 that was all we used.

john poole
bellsouth business
columbia,sc

 

[tnphoneman]

Quick test is to move it to a different port if you have not tried that already. Could be a problem with the port on that card.

 

[Triton101]

If you punch down other Loopstart trunks to the same TN that this one is on and they WORK, then I would have to say it's a CO problem.

Just make sure that TIP and Ring are punched down correctly, or just try reversing them.

 

[MetlePro]

Yea, I've already tried it on another port and the same exists. Also tried another line on the same port of the (faulty line) and that line works correctly, That says to me that my trunk card is working correctly.

I will have to check the grounding.

johnpoole, I'm in Suriname, there is only 1 ISP/Carrier running the whole country, and they only provide loopstart trunks, go figure


Pro reffers to my company, not my status

 

[acewarlock]

You could also try reversing the TIP and RING on the crossconnect to see if that would help.




This is a Signature and not part of the answer, it appears on every reply.

This is an Analogy so don't take it personally as some have.

Why change the engine if all you need is to change the spark plugs.

 

[TAnselm]

When I say ground fault I talking about either the tip or the ring side of the circuit having a low resistance to ground. This could be on the cross-connect shorting out between commercial comm block and your main frame or it could be the lightning protection block. It could even be outside your building. I would remove the cross-connect and check each side both way with a Ohm meter to ground. If you see a short inside, run a new cross-connect. If you see a short outside, call your provider.

 

[MetlePro]

Thnx for the help guys.
The provider is looking into it. After they came by and saw the problem they were conviced it wasn't the pbx's fault.


Pro reffers to my company, not my status

 

[johnpoole]

they were conviced it wasn't the pbx's fault.

very strange thing to hear.. your not really looking at voltage but current.. if that is below 20 mil, the trunk card will not sense it... BUT, how did the cp get into the mix? when you call in on that trunk and trac it, does it show idle? if so your right, if it show a call then it's not the provider but back in the switch...

your right it does sound like a layer one from the provider.. have they change the lens (tn) on there end?

john poole
bellsouth business
columbia,sc

 

[MetlePro]

Yes we did trac the incoming trunk, and it shows idle.

Well initially the line is forwarded to the cp. But since the problem we have forwarded it to a normal analoge set, for testing purposes.

They have a hunting setup at the CO for the incoming trunks.
For the time being, they shorted the faulty line, to make it ring busy and forward to another incoming trunk, while they check into it.
They haven't contacted me yet with any progress on the line. For now customers are able to reach the company, so the company in question doesn't worry too much about it.


Pro reffers to my company, not my status