Called party cannot hear - Comcast Business Class "analog" Lines

[pvision]

One of our customers is running IPO500V2 R9.0.5 with Essential Edition and VM Pro, 2 Combo cards with 6 incoming analog lines from Comcast Business Class (Arris EMTA-not sure what model) and 8 digital phones. They have been reporting intermittent problems with called parties not being able to hear them, and DTMF tones not registering on the other end. I believe it to be a Comcast issue, but they are of course telling me that both onsite and remote testing and review of logs indicate that everything is working properly on their end.

They have just replaced the EMTA, and I'm waiting to hear if that resolved the issue. On my end, I have already rebalanced the impedance on the lines, and double-checked the cables running from the EMTA to the analog jacks on the IPO (IPO RJ45 connector with ring on pin 4, and tip on pin 5 - other end is RJ11 with ring on 3 and tip on 4).

To me, it seems like a carrier issue. Is there anything else that I should consider, or IPO settings that I can change, that might help to resolve this problem?

 

[pvision]

Does anyone have thoughts on this, or experience with helping Comcast to resolve this type of one-way call problem? Called party not hearing voice or DTMF tones seems to be a common problem with Comcast in our area, but the customer unfortunately thinks it is the IP Office system. Regardless of where the fault lies, I just want to get it resolved as quickly as possible.

Thanks

 

[derfloh]

You could perhaps test of it is a line related issue or an IPO issue by connecting an analogue phone directly with the line and test. If everything is fine it is an IPO problem. If you have the same issue it is the provider's problem.

 

[IPGuru]

Have you tried connecting a test but to the line & making test calls?

if they work you have an issue with the IP Office. check all settings & cabling

if not then you need to call Comcast back, preferably as a joint visit

we don't use anlog lines much in the UK & from what I see here we also have a simpler system with far less complexity

"Business class analog lines" - there is an oxymoron if ever i herd one ;-)

A Maintenance contract is essential, not a Luxury.
Do things on the cheap & it will cost you dear

 

[montyzummer]

like a herd of cows

APSS (SME)
ACSS (SME)
ACIS (UC)

 

[pvision]

Good suggestions. derfloh, I agree with your approach, but I have not figured out a manageable way to do it. The problem is frequent but intermittent, SEEMS to happen on all 6 lines and extensions at different times, and by the time they realize it is happening, the person on the other end hangs up. I thought that if I could duplicate the problem live, I could plug an analog phone into the same line before it hits IPO, and see if the other party could hear me on the analog phone. However, no such luck yet.

The other current challenge with troubleshooting is knowing what analog line is in use at the time the problem occurs. Since the extensions are currently programmed with call appearance buttons vs. line appearance buttons, the customer has not been able to tell me which line they are on when the problem occurs. I may have to reprogram the buttons temporarily with line appearance buttons to see if I can narrow the problem down to a particular line.

IPGuru, we are making sure that all visits with Comcast are joint. Also, once the dust settles on this problem, I plan to look into SIP or PRI options, assuming they can get out of their contract for the analog lines.

 

[derfloh]

You can find the used line by starting a SysMon trace and give the users a button 'log stamp'.

So you can easily find the right call in the traces to check which line is used.

 

[amriddle01]

One way/loss of audio is an IP audio issue just as crackle/hiss is typically analogue/digital. I will wager these "Business Class" analogue lines (I would like to know how the differ from analogue lines) actually convert to SIP at the customer premises/in the exchange and this is where the loss of audio occurs, it simply isn't an analogue type issue, at least I/nobody I work with have ever seen it (unless it converts to IP)

 

[pvision]

I forgot about SysMon, and didn't know about log stamp. I just downloaded the docs to read through, and started the program on the server. Any suggestions on useful things to monitor on a regular basis?

 

[derfloh]

Default filter options should be OK.

 

[pvision]

amriddle01 - You are right about the lines coming into the Comcast box as IP (possible SIP), and are then converted to analog, where it enters the IP Office. The one-way loss has to be occurring on the IP side, either during the conversion or after it leaves the EMTA to go back out to the carrier. I mentioned this to the Comcast tech a few days ago, asking him if it was even possible to have one-way loss on an analogue signal. He said no, and shortly thereafter agreed to replace the converter box. Today was the first full day with the new box, and there were no reported incidents of the one-way loss. However, since the problem has been intermittent, we'll have to see how the next few days go.

Thank you all again for taking the time to help - I always learn a few new things each time I post.

 

[teletechman]

Had a charter issue where the route/modem they provided had a flood attack control that would drop every 11 packet. Was told by the Provider Charter that it would not cause a problem (BS). This was on a SIP to PRI handoff and it was causing one-way audio for about 10-20 seconds. We all know that voice needs all of its packets so we had them replace it after much fighting from them and haven't heard an issue since.
Mike

 

[pvision]

Customer reports that since Comcast replaced the EMTA last week, the problem with the other party not being able to hear seems to have magically gone away. They are still reporting instances when DTMF tones stop registering in the middle of a call to a remote IVR, but indicate that it is happening less frequently. I had assumed that the two issues were related, but perhaps there is something that I can do on the IPO side to help with the DTMF issue.

 

[Jerrberr]

I have several problems with Comcast, the real issue is that they originate analog off the local box and it is substandard to a CO analog line. I have long wait times until we get ring tone after dialing and some bad connections as well. One good suggestion is to run the impedance match under lines=> analog options and in the middle ,impedance match. click start and let it run its course, takes a few minutes but it will isolate the best impedance. That can only help you with dealing with Comcast, it helped a little with my problems but Comcast still is causing quality issues.

 

[pvision]

I feel your pain, Jerrberr! We had similar issues in the beginning with long waits for dialed numbers to go out, lines not releasing, etc. The impedance match definitely helped with some of problems, as did increasing Disconnect Clear to 750ms. I suspected problems with the local EMTA box as well, but it took many calls to finally convince them to replace the box despite their insistence that the old box was not showing any signs of problems. Since many of our smaller customers are currently locked in with Comcast, I've been relying on the more experienced members of this forum for suggestions on how to tweak IPO to compensate wherever possible for the apparent substandard quality of these lines. I also plan to do some additional research on my own, and I will post anything I find on this forum.

 

[derfloh]

Strange... Everyday another problem with Comcast. Unbelievable!

 

[Jerrberr]

Glad to help, this was one of my last threads on Comcast lines, my have some more info that could help too. Like # after the number is dialed overrides the wait and executes the call shortening the delay. I'll update too if I find anything else.
Jerrberr

 

[Jerrberr]

http://www.tek-tips.com/viewthread.cfm?qid=1735753

http://www.tek-tips.com/viewthread.cfm?qid=1736125

Here are other threads addressing Comcast issues..

 

[derfloh]

So perhaps it is worth to write an own FAQ only for Comcast ;-)

 

[AndrePa]

I've seen many issues with Comcast and their analog lines via arris cable modem.
Another issue I had with Comcast, is multiple IPOs on SCN, getting knocked off intermittently.

Use your butt set directly on the analog lines on Comcast box, see if You replicate the intermittent one way audio.
Also If you have "Automatic Impedance Balance" on IPO, try setting it to 600 ohms. 600 ohms usually works well with Comcast arris box.

Andre