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Posted By: orion3311 Comdial DXP - PRI Issues (echoing bad) - 09/26/07 08:38 AM
Well I'm back with this year's unsolvable DXP dilemma!

We're running a Comdial DXP w/2 PRIs as our main 2 trunks. The ARS is programmed to go through one PRI and then the other, so one PRI handles most of the calling (the other was really there for expansion/conference calling).

As of about a week ago, we developed a severe PRI echo/slippage issue. Some calls go through fine, others slip so bad that the voices sound robotic and there's a lot of echoing and/or completely cutting out.

I had our phone vendor look at the system, they see nothing wrong. Telco looked at/changed a few things on their end to no avail, they had Verizon do intrusive testing on the lines and they say they're clean to the smartjacks.

At this point everything is starting to point to our system and the wiring. I checked the wiring on the 2 PRIs from the smartjacks (1st floor) to the pbx, and found the the second PRI (unused) had pins 7-8 crossed, which really shouldn't matter as far as I know. I moved the 1st PRI to a spare run and that didn't seem to help - still echoing.

Anyone have any ideas?

Incidentally, since I know it'll come up, all PRI channels are set to nominal padding in VMMI.

(I'm not the installer, just the system admin here who's very phone-savvy :-))
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 09/26/07 08:39 AM
Also...

I have all channels on both PRIs mapped to a console box at our receptionist desk, and saw the echoing when selecting random channels of both PRIs.
Pad -2 DB loss and retry. Not going to fix your slippage problem though.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 09/26/07 01:28 PM
Will try that if we get other probs resolved - we did get echo occasionally but not all the time. Now its full time.

Question - right now the system is simply reporting "sync found" and "warm start" errors. If I go into VMMI under System --> T1/E1 alarms, and set all options to have a threshold of 1, would that then log those types of errors? The telco was asking if theres any way to get advanced diagnostics through the pbx (DXP).
Yes. At least that's the way I do it.

Justin
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 09/27/07 01:52 PM
Ok this is interesting...after seeing many many errors the past few days, Verizon "tested" the lines clean, and in addition, I moved our main PRI to a different run to see if it was noisy at all. I haven't gotten an error since then, but the echoing is still baaad - literally like the announcer at a ball field bad. Makes our music on hold sound interesting though.
when in doubt change the syn card, the T-1 PRI card and the services card. One at a time. In that order. See which one clears the problem.

Jim Hoey
SST Communications
Long Island, New York

6319560100
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/01/07 10:59 AM
Wow I was actually thinking that. Thing is though, ever since I looked into the wiring I've gotten zero errors. I even enabled all the advanced logging options - nothing. Could that still be the sync card? Its currently set to get timing from the telco.

Replacing the PRI boards would be expensive at over $xxxx a piece (used). I doubt its them since both PRIs have the same problems.

[Please don't include any pricing in the open forum. Thanks!]
Posted By: jwooten Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 04:57 AM
One way this might be troubleshot is to connect your Pri boards back to back. I've never had an occasion to do this, but logically it should work!
Posted By: CMDL_GUY Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 05:11 AM
Quote
Originally posted by jwooten:
One way this might be troubleshot is to connect your Pri boards back to back. I've never had an occasion to do this, but logically it should work!
It will work, good idea. :thumb:
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 06:58 AM
Ahh that IS a good idea...if I were to do that, I should just call one of my DIDs? Also, I assume I'll need a T1 style crossover cable for that?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 07:01 AM
PS - if anyone knows a reputable Comdial/Vertical dealer in my area (Bucks County, PA), who could deal with the DXP, I'd be interested in knowing. Our current dealer whom I used to really like are seriously dropping the ball - called twice to see if they could try swapping the syn card for us - no call back.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 07:04 AM
PS - If I do the connect the PRI boards, would I have to switch the sync card for it to provide timing?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 08:07 AM
FYI - Just tried it using a T1 crossover cable, and while the lines showed connection, they showed as disabled on my line console. I couldn't make any calls across them. I tried setting the sync bother to auto and manual with no changes.

I reconnected PRIs, rebooted the system, and tried both options on the sync card again, changing both the timing switches and what line it gets timing from (pri/sec), and nothing changed. Still have echo. Made several calls home, and in most cases I could hear myself, then 2 of the calls my mom could hear herself echo but I could hear it.

One key thing seems to be that when the call is answered, there's a loud PSSSHT noise. That seems to be consistent with the static.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/02/07 08:49 AM
Finally got a hold of someone with some pull at the vendor - they're going to send someone out to do whatever they can to test the DXP, be it swapping the syn card or doing the crossover trick.
Posted By: nonameyet Re: Comdial DXP - PRI Issues (echoing bad) - 10/03/07 10:51 AM
So, did your Vendor show up yet?
How did you make out?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/04/07 12:27 PM
Well they came out yesterday and swapped the syn card, but it still echoes. They mentioned the crossover cable test would work but with a lot more work than just plugging the it in - he mentioned something to do with the dip switches on one of the PRI boards would have to be modified, I guess to assign FXO capability to the channels instead of FXS (hopefully that makes sense).

He verified the wiring looks ok and we even put a loopback adapter on each PRI board to see if it would sync to itself. They worked fine.

Back to the carrier! Two calls into them today with no return call.
Posted By: p2ii Re: Comdial DXP - PRI Issues (echoing bad) - 10/04/07 12:48 PM
Has the carrier checked the echo canceller in the central office or, if it is fed by a SLC or Lightspan, the cards in there? Intrusive tests basically just test the loop(cable pair/s) from c.o. to smartjack.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/04/07 03:00 PM
Well the quick update is that I called the carrier again over and over until I got a live body. He is having them do instrusive testing again tonight, and also dispatching someone out to look at the lines physically, I guess from Verizon.

I got the echo myself a few times this morning, even though I'm one of the few that doesn't see it much. I don't make nearly as many calls as others in here do though, for our sales people thats all they do.

Another ironic thing is that when I call the carrier, I always hear a clicking/popping noise, that I can best describe as a hookflash. Its only when I call them though, and the guy swears he doesn't hear it. I still think its on their end.
Clicking and popping on a PRI is typically caused by slips, in my experience.
Since the presence of echo on PRI's can be caused by old or unbalanced hardware devices on a carrier's network, is there a way that the presence of the echo can be isolated to only the local or long distance calls?

I also agree with p2ii, that the provider may be unaware of a possible problem with their echo cancellor, which is many times not included within the circuit path during the actual testing.

If a tech is dispatched, place a call to the carrier, so that the tech can physically monitor these clicking sounds that you're hearing.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/05/07 12:05 PM
Well Verizon came out and tested the main PRI, and would have tested the other one had he found anything, but he said its perfectly clean and within 4mhz of the ideal signal. He was going to test it to Level3 (not sure where they are in the mix) but couldn't get anyone on the line to test with. He also mentioned doing an "Octet 55" test, which he claims "beats the .... out of the line". That test passed perfectly.

As soon as he left the provider called up again and we bounced heads, but once again he swears its our PBX. I told him I highly doubt it - and once again whenever I talked to them it clicks/pops and literally cuts out. His answer? Coincidence. I told him 10 out of 10 calls to him with that symptom is NOT coincidence, but we may coincidentally be contacting another provider soon. The Verizon guy agreed that echoing that we're hearing is coming from the network or far end, not our own system. Even if it was echoing, it wouldn't have the delay we're seeing.

I'm curious if anyone is seeing simliar things...our provider is Capital Telecommunications, which was recently acquired by Starvox. Because of this, I'm assuming we've been switched to a VOIP backbone.

https://blog.tmcnet.com/blog/rich-tehrani/voip/starvox-voip-funding.html
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/09/07 12:12 PM
I was told by my phone vendor that the COFA/B8ZS lights are nothing to worry about. Are they? They're both solid "on" on both PRI boards. I don't have documentation on the DXP boards but found documentation on the FX boards that if the dipswitches are defaulted, that the light means there's COFA errors.

As a quick update, not only did we get slammed with a huuuge phone bill from the provider for "accounting errors", but today, both COFA lights are on, we're getting a lot of "Network Busy" errors trying to call out, echoing is as bad as ever, and now some of our outgoing caller ID info is showing up as a Georgia 404 number (we're in PA).
Change of Frame Alignment usually isn't much to worry about, in my experience, but I could be wrong on the "not much to worry about" part.

Can they change you over to a maintenance circuit, and possibly change out the NIU, to help rule out the circuit? Also, is there any kind of doubler equipment involved on their side?

Justin
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/10/07 06:22 AM
Well I finally got through late yesterday and apparently they had some "network-wide" issues that caused the network busy stuff, but the guy was stunned on the Georgia caller IDs.

I dug around my buddy's used equipment warehouse trying to find an old phone system that does PRIs, but while he had many systems (phones and boards), he trashed all the controller boxes. Makes perfect sense, right?? *sigh*

Their days as our carrier is numbered.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/10/07 06:47 AM
Got a call this morning, and they temporarily switched us to a different long distance carrier (no billing affected) to rule out their network. They claim they've handed our ticket to every senior level tech they have to no avail, and are as frustrated as we are (yet the VP never returned my call).

They STILL say it may be our PBX.
Posted By: nonameyet Re: Comdial DXP - PRI Issues (echoing bad) - 10/18/07 11:27 AM
So, it's been a week, What is the status?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 10/22/07 12:04 PM
Sorry was a away on vacation/business. Well as far as I know - there was still echo in some cases, although it seems substantially less complaints anyway. They since switched us back and the echo is back with a vengence.

Of course the first day I was away - we lost long distance completely which they say was a level3 prob.
Posted By: nonameyet Re: Comdial DXP - PRI Issues (echoing bad) - 10/23/07 01:13 PM
So, I guess its a Carrier Issue?

NOT Your Vendor!
Posted By: nonameyet Re: Comdial DXP - PRI Issues (echoing bad) - 10/29/07 02:07 PM
Where are we with this issue?
is it fixed? and what was it finally?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 11/02/07 09:42 AM
I was afraid to ask but someone still complained about echo on Wed, so its still there. We're officially switching carriers at this point.

The carrier has now offered to swing in 2 new PRIs, to (from what I understand) switch OFF of their native network (prob running VOIP) to another carrier who they partner with (probably Verizon). While that would have been an option if they offered to do that 10 days in, we are now practically 45-50 days in and getting responses back from them has been like pulling teeth.

From what I understand in talking to some of the telcos (and getting some inside info), that indeed we were prob switched over to a softswitch. As I mentioned earlier Starvox is primarily a VOIP network so they're prob routing all our long distance over a VOIP platform. All the symptoms are synonomous with VOIP.

So at this point, no the problem was never actually fixed, but hopefully a new carrier will resolve the issue.
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 02/19/08 12:13 PM
Well...4-5 months later, we switched to Verizon, and the echo is back. I'm at a loss. Anyone know what could cause echo and dropped calls? Doesn't happen as much as it used to but still happens.

Would a CSU on the PRIs help?
well you said you had two pris. have you pin pointed what card your calls are going out on that give you the echo? see if you can change your cards in your switch around and see if thats help. maybe you can pin point it to a card. if that don't work have the telephone company then put a t-bird on the pri if they can and see what they find. thats what i would do just my two cents
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 02/20/08 01:33 PM
It seems to be both cards. They're sort of set up in a round-robin scenerio where incoming calls start on channel 1 of the first pri, while outgoing start on the last channel of the second PRI.

As an update...in going through EVERY setting, I found the switch protocol is set to DMS100, it should be 5ESS. Son of a ....
Posted By: nonameyet Re: Comdial DXP - PRI Issues (echoing bad) - 02/21/08 07:35 AM
are you xxxxxxx kidding me?

Is that really what was the Issue the entire time?
Posted By: orion3311 Re: Comdial DXP - PRI Issues (echoing bad) - 02/21/08 01:44 PM
Sigh....well that was short lived. My partner called me for something this morning while I was driving in and in the middle of talking she said "wow do you hear that echo??" (I couldn't hear it but she could hear herself).

@##$#@$@#%@!!!!

So apparently changing the switch protocol didn't help. It was prob just wrong since we switched to Verizon, but amazingly the lines were connecting fine.

Per our vendor, we're going to try bumping the transmit padding down 2 notches to see if that helps.

As for the dropped calls...I believe I was the culprit there. I was setting the default outbound caller ID setting under the ISDN board screen, and didn't realize it reboots the boards when you apply the settings. I prob killed all kindsa calls that day ;-)
Through all of this, have you been looking for chronic problems in the T1 log on the system?

Adjusting the padding may be a good place to go. Good idea on your vendor's part. It seems like you've described the echo as being uni-directional, so you should be able to adjust one side and have some sort of affect on the echo.

Justin
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