BCM50 R2 doesn't trip rings

[rrmass]

I have a customer with a BCM50 R2 that intermittently didn't trip the rings on incoming calls on the 1st line. The call comes in to the assigned set and displays the caller id but when they answer, it doen't trip the ring and they just hear a very loud ring. The caller would call back again and all would then be fine.

The first thing I did was replace the power supply but the problem was still there. As they are only using 3 of the 4 trunks, I next moved the jumper from line 1 to line 4 to determine if the problem was with the BCM or the telco. The problem persisted so since it moved I thought the problem could be the ring trip circuitry on the line card at the telco not detecting the off hook from the BCM when the call was answered.

Unfortunately the customer says it happens on some of the other lines as well so there goes that theory.

I'm going to replace the BCM but I'm still wondering what the problem could be as I looked up the data sheets for the chips that interface to the telco line and they all seem to have separate ring detect and off hook circuitry per line. They do have a common bus (SPI) for their control signals though.

Does anyone think this could be a software problem as in my mind thats the only thing along with the SPI bus that would be common to all 4 lines.

Any thoughts on doing a factory reset on this unit to try to resolve the issue. I know I should just replace the unit and toss the old one but sometimes I just can't leave these kind of things unresolved. One could learn something you know.

 

[curlycord]

Measure the voltage on each C.O. line
Should be 90v when ringing so have your test set call in then measure with the meter.



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http://www.curlycord.com

Toronto Canada

http://www.telcopc.ca

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[rrmass]

Shall do, 90vdc pulsed at 20 cps right?. I'll measure loop current while I'm at it too, although I don't think either will be out of spec as I'm only 4 blocks from the C.O.

 

[allworxguy]

Did you test this with a butt set and not the BCM? Being 4 blocks from the CO you may have an over voltage condition.

Marv ccna

http://www.telemarv.ca

Sales, Installation & Service for Norstar, BCM, Samsung & Allworx Serving Ottawa and Eastern Ontario since 1990

 

[exsmogger]

You want to be around 30mA line current. If it's too hot it might have damaged the analog line circuits on the BCM.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952

 

[rrmass]

You mean ~30ma with a 600ohm termination, yes? I find it difficult to understand that the analog line circuits for each line would all go bad at the same time since from my investigation they all seem to be separate circuits although it's definitely not impossible.

I've been away from telco for >10 years (got sucked into IT), in a previous life before that I spent 31 years and change working in the C.O. thats 4 blocks away.

I don't ever recall a situation where over voltage/current would prevent a ring trip, actually the opposite under current can have the off hook detectors in the C.O. fail to trip rings.

The one thing that I have seen over current interfere with is transmisson. I have seen issues with modems that are confronted with over current from being too close to the C.O. The high DC current saturates the transformers in the modem and then they don't work worth a darn without adding some sort of attenuation.

Oh well, I have aqcuired another BCM50 to replace it and will do a replacement to get the customer going. I will still keep on banging on the bad one to see if I can find the issue. Sometimes you just can't drop a problem until you've beat the crap outta it.

 

[curlycord]

If it is the BCM we can make it use SIP lines instead so don't throw it out.

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Add me to LinkedIN

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http://www.telcopc.ca

 

[Firebird Scrambler]

As you have analogue trunks, Was your BCM originally configured with the correct country type setting?. Also, are your trunks loop or ground start calling?.

Firebird Scrambler
Nortel and Avaya Meridian 1 / Succession and BCM / Norstar Programmer

Very advance high level knowledge on the Linux BCM phone system.

Website

http://somertel.com

 

[rrmass]

The trunks are loop start and the country setting is and always was correct.

Correct me if I'm wrong but I assume you're wondering about the country code setting as it would affect ring cadence and frequency. If that is the case I'd think that if the BCM had the wrong country code it may not detect incoming rings. In my case the BCM is detecting the ring, signaling the appropriated sets that have appear & ring for the line and even cutting through audio to the set when the handset is lifted but my customer only hears a loud ringing in the handset which would be the ring voltage coming through the audio path.

In my estimation the BCM is detecting the ring and cutting a path through to the set but either the BCM trunk is not applying an off hook to the line to tell the C.O. to stop the ringing and provide audio cut through or the C.O. is not detecting the off hook and failing to stop ringing and providing cut through.

This problem is very intermittent, only a few times a week so I'm in the process of programming a replacement BCM50 to determine once and for all if the issue is mine or the telco's. Of course the telco will not take any action unless you have the proof right in front of them.

 

[Firebird Scrambler]

Yes, I was wondering if the wrong country type had been used in error as I came across this problem recently with a customer who had a PRI trunk issue set to 24 trunks, when was meant to be set to 30.

That had me thinking for a while!.

The Norstar and BCM systems are prone to extra ringing cycles on external calls with analogue trunks and this can be a problem when more than one phone in the office is set to ring on incoming trunks.

I'm guessing that none of the trunks go to voicemail first?.

Firebird Scrambler
Nortel and Avaya Meridian 1 / Succession and BCM / Norstar Programmer

Very advance high level knowledge on the Linux BCM phone system.

Website

http://somertel.com

 

[rrmass]

No voicemail on this system at all, only keycodes for 4 analog trunks and 12 digital sets.

Three trunks are equipped and ten T7208 digital sets with appear & ring on all sets.

Can you expand on what you meant by Norstar and BCM systems being prone to extra ringing cycles on external calls with analogue trunks.

Thanks

 

[Firebird Scrambler]

In the UK, we have noticed that in a number of cases where you have more than one phone that is set to ring on incoming calls, that once the call has been answered that the remaining phones continue to ring once or twice and this seems to only be on analogue trunks.

It's like it is an over ring that happens.

Firebird Scrambler
Nortel and Avaya Meridian 1 / Succession and BCM / Norstar Programmer

Very advance high level knowledge on the Linux BCM phone system.

Website

http://somertel.com

 

[exsmogger]

Firebird, are these truly analog trunks on which you see this problem? More and more I'm seeing so-called analog lines being provided by cable companies that are really SIP trunks with a converter box that outputs analog trunks. They don't play nicely with legacy fax machines or credit card machines.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952

 

[Firebird Scrambler]

Morning Brian

I used to see it on Norstar systems and we didn't have the internet, like we do now. I agree that the SIP to Analogue converters are becoming more common these days and they bring along their own problems.

Firebird Scrambler
Nortel and Avaya Meridian 1 / Succession and BCM / Norstar Programmer

Very advance high level knowledge on the Linux BCM phone system.

Website

http://somertel.com