Siemens and ground start trunks question

[Signo]

First off I know nothing about Siemens pbx's. I have done Nortel and now Avaya for the mom and pop phone company I work for. I am a C.O. tech and part time PBX guy.

The issue is I have a customer with 20 ground start lines into a Siemens PBX (some version of a hi-path). The ground starts are transported over two channel banks that are back to back connected over a fiber link from a remote central office switch. All this is necessary because ground start is obsolete and we have limited capacity to provide it. I can ground start all 20 lines fine at the nid but the customer out of the blue says they can not make calls out.

I have been to the site and when you out-dial using a 5 and dial the number the system just sits and after about 1 minute the phone display show "currently not possible". I feel like the system has a problem, but and looking for some info from a person who knows Siemens equipment.

I don't want to be the guy who just walks in ground starts the trunks says it your problem and bolts. We are in a rural area and no one want to come out to work on the system so I am trying to help them.

Any insight would be greatly appreciated.

 

[sbcsu]

Make sure that the PBX itself is grounded/earthed.
Without a good earth connection to the shelf units the ground start wont work.
It is not enough just to put an earth via the mains electric cable you have to ground the unit itself.

Reset the cards that run the trunks.

 

[birdseye51]

Unlike loop calling lines Ground start lines are polarity conscious. Incoming will work irrespective of the polarity but outgoing will fail if the polarity is reversed. Using a test phone on the frame you can check the polarity of these lines. I find it difficult to believe that all the lines are reversed but if the trunk group search mode is set ascending or descending then the trunk selection will always be the first trunk in ascending mode and the last trunk in descending mode. Changing the search mode to circular will improve the issue but certainly the polarity of the lines need checking.

 

[Signo]

I was thinking about the polarity yesterday and checked my line cards at the CO and they are not polarity sensitive on the frame and can be ground started from the tip or ring side. One of my coworkers and I were wondering if the system was tip ring sensitive, but figured if the CO cards didnt care the system should not care. I will check it today just to be sure. I didnt look at the chassis ground but will verify it also. I have been told by my management not to login to the unit since we dont own it and dont want to take on the liability so i cant check the trunk group search mode.

I would think that if the the first trunk was dead the system would just move on to the next one after a few seconds. But if they all are reversed that would explain the long pause as it checks all the lines in the group then fails out. I found out that there was a self failure that the trunks run though early this week in the CO and maybe they are all polarity opposite. One of the guys I work with had to swap in a new shelf that was a different brand. Gotta love finding out this kind of stuff a day later. That would explain the incoming only but no out going seizure.

Thanks guys your help is very much appreciated, and gives me some solid leads to check.

 

[PERRYPJ]

You need to remove the switch from the lines to test for polarity, you should only get dialtone when you ground the ring side of the line.

OLD ROLMEN WORKING ON NORTELS AND AVAYA

 

[Signo]

Sorry about the late update.

I went out and worked with the customer by reversing the battery on some lines to test. When reversed from their original position the auto attendent on the system would not even answer anymore. So reversing the battery made the problem worse (no incoming or outgoing). I put them back to their original position and inbound worked as before but the system still will not dial out.

As for removing the lines from the system and checking polarity it makes no difference what side I ground on the line it will start. These line come out of a old stromberg/Siemens DCO and on the frame in the central office I can ground start from either side.

As far as I can tell the lines are ok and the system has some sort of issue. The customer has decided they are to cheap to call in a Siemens tech, so I told them I am done.

Today they called in a complaint of incoming calls fading in and out and dropping completly. If it already cant make calls out then a few weeks later you start losing incoming calls its kind of a no brainer.

These are the kind of people I am dealing with, so I gave up.

My last advice was to pay a person who knows that brand of equipment.

Anyways I would like to thank everyone for there input and advice with this issue.

 

[donb01]

While just telling them can probably get you in just as much trouble as doing it yourself, I would tell them to yank the CO card out of the switch a couple of inches, wait 10 secs and shove it back in until it bottoms out. When I can't figure anything else out I will always do that. First it reseats the card in case there was a poor connection someplace, and secondly it lets the card reload its software in case there was some software glitch going on.

I have always had a good relationship with my techs, and one of their favorite expressions is "If all else fails, give it a good enema (soft restart)"....

The instructions tell you to shut the card down properly first, but I have been reseating cards this way for 13 years and it's pretty rare that one doesn't just come back up and work. The board would probably be a TMCOT board for ground start trunks on a 9006 system.