I've been experiencing an intermittent ongoing problem with a site that incoming callers receive busy signals for no apparent reason. Happens about once a month. It happens on any DID number dialed into the system. Today I saw 27 yellow alarms once I reset the system to look at the alarms. It's not a high traffic situation. Everything else in the system seems to function fine when the trouble is occuring. AT&T has checked the T1 on several occasions and has indicated that there is no trouble on there end. As a precaution they tell me that they did replace their equipment in the CO. I'm using the combo T1 / PRI card, verifed my settings numerous times with tech support, everything is set correctly. I'm also using an Adtran ACE CSU. AT&T will usually show the trunks busied out in their switch when this occures, they tell me this is automatic thing. A reset from their end or from the XTS will clear the trouble in a couple of minutes. Anyone experience this type of trouble on an XTS? Is this T1 / PRI card pretty reliable? Tech support says to run etrace and leave a laptop connected indefinitely.

Any suggestions would be appreciated. Thanks!

If you're getting yellows the far end is loosing signal.

Greg:

First, what software is running on the XTS? Second, what kind of switch is at&t using? If it is not a real switch (DMS, ESS, etc.), you are going to have problems. Try to get someone at at&t to verify the serving switch and we might be able to help with suggestions.

Ed, this reminds me of the STS PRI troubles at our common customer site in Fredericksburg.

I will check into that tomorrow, thanks for the input.

Also, I'd like to hear more about the STS PRI problem. I had one installed lasy year and it was on a Cisco soft switch. We encountered numerous problems loosing sync.

NIU, facilities, soft switch. these are just some of the things I have dealt with. I've only had two bad XTS T1 boards ever. While fighting with the provider, I usually show my customer where the line in is located on the CSU. By unplugging the T1/PRI at that point, there is no keep alive to deal with. Then when plugging it back in, a loop back almost always resynchronizes it. While this doesn't completely rule out a local hardware issue, it really suggests that it is something in the CO. What I really hate is when the CO loops it down for testing, says no problem found, then loops it back up. They just don't seem to realize that the act of looping it down and up resets the circuit. It is now up to us to do part of their work for them before they invest a knowledgeable tech on our trouble ticket.

I have more information regarding the my XTS PRI issue.

The Vodavi system has V.300-2FE3 software,
the AT&T circuit is on a 5 ESS switch.

They did tell me that it is on a combination of fiber and copper by the time it reaches the customer site.

AT&T has issued a cronic trouble ticket on the problem and they're looking into it.

Any thoughts on what I might be able to do on my end? Thx.

How far away is the central office the pri originates from? If you are at the end of the loop you could have problems. That was the issue with the STS pri that keep dropping in Fredericksburg.

I'm guessing aprox 8 to 10 miles. I do know that this same customer also has aprox 3 other T1 circuits for differnet data applications that are pretty trouble free. I would assume with data applications they could keep retransmitting packets and you might never be aware of this if there was trouble, where as with voice you would definitely experience audio problems.

If we are at the end of the loop do we have any other options? Go back to pots lines? They may be old and traditional but at least they work.

If it is 8 miles of copper...its a major issue. You might try cheating the CSU and set it for a longer LBO and try to boost the signal a bit and see what happens.

You might want to insist that they check with at&t's local plant manager and verify that the cable pair being used isn't half-tapped. I have one customer who had the same problems that is located less than a mile from the CO. When we first installed the system about 8 years ago, there were constant crashes, almost daily. I knew that GTE had half-tapped an existing cable to feed this building when it was constructed, so I just took a ride further down the road and followed the cable route (aerial).

Turns out that it continued about six more miles from my customer's site and yes, I finally had to open a pedestal to prove to them that the pair count was in fact half-tapped (GTE denied it). They agreed to cut the affected pairs dead to the field and it worked perfectly after that.

Until........

The customer downsized and eliminated one of their two PRIs. In (now) Verizon's usual fashion, they installed a new single circuit instead of just eliminating the second one as requested. Within a day, same song, second verse. It was crashing constantly and all that Verizon had to say was....Well, let's not even go there.

In a conference call with God only knows how many people, I was lucky enough to have a CO technician involved. He agreed to run a full test on the T1 at the frame for the night and give us the results in the morning. Oh boy was he surprised the next day in our conference call.

Although he was insistent that this was an F1 cable count, which it technically is, their plant records didn't show that my customer's cable count was a tap. I hate to think of the hundreds of hours of visits, emergency calls, conference calls, etc. that were wasted (once again). Once they moved our circuit back to the original pairs, everything has been fine.

Oh, by the way: Our affected cable pair was found to be bouncing around in the breeze; an aerial drop that fed a now-removed mobile home two miles away.

Sorry for the lengthy side-track, but I just thought I'd share this experience in an effort to give you some ammo. Vodavi has said to me many times that a problem with a PRI is always on the telco's end and I can say with certainty that this has always been the case for me. Good luck.

Half tapping....I didn't think about that. Reminds me of the time long ago when a customer of mine with 22 pots lines in hunt that kept getting ring no answer. I argued with Bell Atlantic now you know who about it for days about whos fault it was. Turns out that when a truck drove by a ped down the street, the vibrations would shake the ped and one side of line 7 would disconnect from the screw termial on the wiring block in the ped thus opening up the hunt. The next truck to roll by would shake it again and it would start working. You can imagine how much fun this was.

Ed. I agree with you. Any PRI problems that I have ever had were also always on the provider end. While I mentioned that I have had two bad boards in my past, one was obviously bad because it failed a local loop back test from the CSU. The 2nd board wasn't actually bad. It turned out to be that when I went to add the newest combo board, I needed to revert to the older revision because the XTS S/W ver 1.16 didn't support the newer one. That issue is found on older XTS posts in the forum. Neither fault occurred on an existing circuit that was previously in-service but only on new additions. And the 1st one was when I tried to use an old board that was removed from a previous installation. It had probably been mishandled somewhere along the way.

All everyone has said is probably true (network trouble). Still is he's receiving yellows and that mean's the AT&T switch, no matter what kind it is, is loosing signal. So depending on what's on the circuit, as far as monitoring equipment goes, AT&T ought to be able to see that and narrow it down. At the very least they should be able to see the LOS at their switch. I'd think by now most of the NID's would be the smart type that they can pull PM data from also. I think I'd be doing a little more talking to AT&T to see if they have access to PM data.

Thanks for the input, I'll mention this to AT&T tomorrow. They've escalated this to a cronic repair and are supposed to do more testing.

Question; is it necessary to have a csu? What would happen without it?

Thanks

The pri will technically work without a csu but not as well. The csu helps to prevent jitter and signal loss.