Ground Start Trunks 1

[NTOldTimer]

Is there a parameter to control how long the ground will be applied for Ground Start Trunks. We have some that work very intermittently. I can manually ground start them using the same ground reference without any trouble. When I access them through the XUT card, sometimes they work and sometimes they don't. I've changed cards, put cards in a different shelf, lots of trouble shooting. When I listen in with my test set it does seem like the ground is applied for a very short period of time but the TIMRS section of LD 16 doesn't appear to have a parameter to lengthen the time a ground is applied.

 

[ralstonral]

can you say what type of system you and you also need to check the polarity of the lines

 

[GHTROUT]

ralstonral (MIS) Not to speak for NTOldtimer, but being an expert in areas where QPC219, Book 3, and LD27 ARS were spoken, I have some reminiscent respect from him I as I do for him.

Mentioning LD16, XUT, etc - we know it is a M1 of some kind with a version that works in IPE.

Do you know of some issue with ground timing? The polarity thing, as obvious as it sounds, was the most common problem we had in the 1980's - it was intermittent too. When T/R were flipped, it actually worked on some tests.

~
Gene of

http://www.GHTROUT.com

~

 

[NTOldTimer]

Gene,

You are indeed a demi-god! Known world wide for your contributions to our field. Thanks for taking the time to reply to my post.
I have checked the polarity with my test set, tried to reversing the polarity (backwards), upgraded the NT8D14BB to a CA vintage, double checked the jumper settings, and moved cards from one OPT11 shelf to another. I scoured the NTPs thinking there must be a timer that controls the length of time that ground is applied because it seems so short when I listen. I came up with nada in my search but sometimes the NTPs aren't too clear and wondered if someone knew about a variable field for this. At this point I'm thinking I have a ground reference issue but what stymies me is the fact that I can tie a cross cut to the ground bus and pull dial tone every time with my test set. But I do have to hold the ground on there for a second or so. And by the way I can groud start these on the tip or the ring side, doesn't seem to make much difference. If I ground it for too short a period I can make it fail.

 

[acewarlock]

How many trunks?

is it just 1 route or all routes?

is it the same trunks failing every time or different trunks?

How are you determing that you have a groung problem?

Do you just get dead air?

 

[NTOldTimer]

There are 14 trunks and most all of them will fail at least sometimes and this is the only analog route. Some fail more frequently than others, seems especially those on ports 2 and 3 of these two cards (11 and 17). The problem is very intermittent and I have mixed results taking a TN from a trunk that seems to be working pretty well and putting it on a trunk that has been cronic. When I access the trunk from a Meridian phone in maintenance mode using LD 36 I get DN? but no dial tone then TRK017 a few seconds later. This is an Option 11 on RLS 3.0

Of course the telco vendor comes out and ground starts the trunks at the D-Mark and says "see no trouble".

There isn't a variable for the ground timing is there?

 

[johnpoole]

long shot, test the loop current on those trunks. just a shot, but i pulled my old rls 12 books and a ground start pluse timer was not there. i don't remember haiving that problem but your talking a few switches ago.. i used to like the smoke break every time you switched loads.. dn in load 20 tn in load 21 or was it the other way? truth is i couldn't remember back then.. but at the time i only touched a "real" switch when the old guys were on vacation. usually it was 1a2 or crossbar and usi-20's

john poole
bellsouth business
columbia,sc

 

[NTOldTimer]

Is the resistance factor a play here? Am I going to have any effect playing with the TIMP BIMP prompts?

 

[PERRYPJ]

NO TIMP AND BIMP WILL HAVE NO EFFECT. IF YOUR ON THE DEMARC WITH YOUR TEST SET AND JUST TOUCH THE GRD, AND I MEAN DON'T KEEP IT ON YOU SHOULD HAVE DIALTONE. THERE ARE SPECS ON THIS FROM THE OLD BELL LABS, I WILL SEE IF I CAN FIND THEM.
AND JOHN YOU SAID USI-20, DO YOU MEAN UNITED STATES INSTRUMENT 20 OUT OF CHARLOTTESVILLE, VA

OLD ROLMEN WORKING ON NORTELS

 

[GHTROUT]

Finally put some pages from X05, book 3 of 5 in the scanner. Not the answer to this problem, but explainations of the timers when there really were explainations. Good info. It put a link on the opening page - look for the red "New" image (that is supposed to look idiotic, that was my intention!

Here ya go

~
Gene of

http://www.GHTROUT.com

~

 

[NTOldTimer]

Thanks Gene, now I know what a guard timer is (I was seriously wondering). OK so let's say if their equipment is not to spec. and the telco equipment needs a ground longer than bell standards, it would seem that I need some sort of equipment to measure and reproduce timed ground start conditions. Where Am I Going To Come Up With Test Equipment Like That? I'll have to prove my ground is on there long enough and that their equipment needs a ground for longer than the spec. The telco is TDS Metrocom, they'll come out and work with me at no cost, but the test equipment they've produced so far is a standard analog test set and a ground wire. They have fiber facilities (OC48) to the prem (even in the same room) and there are 3 analog cards on their fiber shelf that break out to 66 blocks for the POTS lines needed at this site. The trunks I've been able to consistantly reproduce trouble on are working on different cards of theirs. I'm going out there again on Monday to make sure I've put a CA vintage card in the third Opt 11 cabinet and trunks are failing there too. That eliminates my backplane, power card and rules out any problem I may have been experiencing with the older BB vintage (vintage being an issue is not likely at this point but still eliminating things one by one) What a head banger. I consider this hubmling frustration fun on some level. There's got to be something terribly wrong with me.

 

[GHTROUT]

What I'd prolly do is attack the whole issue is this - and you've probably done some of this if not all... (it is in no specific order)

Measure potential between the iron on your Option and the iron on the housing with their analog cards - then if no potential, measure resistance...technically oughta be zero.

Since you can see TDS's line card that feeds you, I'll bet you can find some dcumentation on the various settings and options the card can be set for. You could plant an idea for something they could tweak if you find something.

No reason not to toggle the TIMP/BIMP setting in LD14 - might be some undocumented interaction that resolves the problem.

Toggle LD14 CLS LPR to HPR

Set the LD16 TIMR ICF/OGF timers to 128, then in the 700's just to see what happens.

Cycle all the DIP switches on the trunk card in case there is a flakey one - unless you've ruled that out in some other way.

Just rattling off some thoughts...

Then, consider changing to loop start


~
Gene of

http://www.GHTROUT.com

~

 

[LanceMI]

Steve,

Call me, I would be will to discuss my thoughts on this thread over lunch