Mitel 5000 LoopStart trunks 1

[magallanr1]

Has anyone ever encountered this. I have a Mitel 5000 customer that is using 3 loopstart trunks on the processor module with 4. So one port is unused. I'm losing my loopstart ports. The first thing I did was move the line from the bad port to the unused one. The trouble followed and I lost the former unused port. My next step was to replace the processor module,which I did. I am now faced with replacing the Processor module again but am trying to determine the exact cause. I do not have a lsm-4 external loop start card. My loops are very short, only 600 ft from the central office. Does this make a difference? Any help would be appreciated.

 

[Hovus]

Could be the carrier is sending too much voltage to the lines and shorting your ports...use a voltage meter on the pairs and check to see that you're getting ~48V DC while the line is idle.

I have dreamed a dream, but now that dream has gone from me.

 

[magallanr1]

Its 48VDC, I was told my Mitel to submit the loop current readings, but they seem normal. I have the exact same system Mitel 5000 VSB across the street and they have no issues. I was also told to install 100 ohm 1/2 watt resistors. I have NO clue what is causing this.

 

[wireman50]

Possibly, and really is only a possibiity, it could be an earth problem. Try measuring the voltage from B to earth and A to earth (i.e. a seperate earth) and see if you are getting any voltage on the A leg. It could also be a stray voltage from some faulty equipment that is leaking onto the lines through earth (remembering that, in the UK at least, earth of the A leg is back at the CO so its not impossible). Its a bit like having earth differentials on network wiring when the supplies are different between two buildings but not the same. Hope that makes sense.

 

[magallanr1]

The customer's alarm line was tied into line 1, I moved it to line 3 to see if the problem follows that. It could be exactly what you are talking about. Other than that they are on completely seperate line equipment cards at the central office. My company is the carrier and my co tech changed the ring generator card just to see if it made a difference. It didnt. Currently the customer is on an LSM-4 that I had in truck stock since I already changed the HX controller module.

 

[619Tech]

When you say "I am losing my loopstart ports", do you you mean you don't see them in programming? You can't access the port via dialing the ports extension number? Are you using individual trunk keys? Is the alarm system tied to the problem trunk or different one? Is there a possiblity of a fax or postage machine intermittently stealing the line?

 

[magallanr1]

This is what happens to the ports, when a call is coming in I am unable to answer it, the phones just ring, even when I have picked up a phone to answer. There are no errors in my logs, no indication that a promblem is there. I know what your thinking, check the programming. I have, and techs with much more experience have checked as well as Mitel tier 3 support. The line is not busy, when a call comes in its unable to be answered via the digital phones on the phone system. When I clip a butt set on the cable block I can answer it isolated the problem to my phone system.

 

[wireman50]

So the ring detect circuit is still working. Can you make an outgoing call on the lines? I'm not trained on the 5000 (my engineer is) but is there a setting in the line config for long and short? This IIRC on most systems applies a restistence to the line for short so that they do not deliver too much current when ringing.Daft question but you have set it for the correct country?

 

[magallanr1]

Yes I can make outgoing calls,and the country is set correctly as I am using there data network as my clock source. I will look into verifying the line config settings.