atcomsystems.ca/forum Forums Other TDM Phone Systems Vertical Telephones & Systems SBX and Comcast Issue

Just looking to see if anyone else has come across this and if anyone has input.

We have a customer who just ported their lines to Comcast from Verizon and within a couple weeks we started getting a report of hearing ringback when answering calls. After testing we found this is a timing centric problem; it only occurs when the customer goes off-hook during the callers ring-on cycle (user phone is not ringing). The user hears the remaining of the caller's ring cycle and no talk path is available until after the tone completes.

Met with a higher up from Comcast at the customer site, he brought a home analog phone and could not duplicate the problem. Our tech connected his buttset and could reproduce the problem.

We swapped out the cabinet, which helped for a couple weeks again, but got another call from the customer this morning and the same problem has come back.

Any thoughts?

I have an SBX in my office with (gasp) Comcast lines and have never seen this. I am using Ver 3.5Aw

Same here. We had our in house SBX (3.5Be) hooked up to our Comcast lines and had no issues, but we could duplicate the sound on the buttset. Hooked up the customer's SBX to our lines and it does the same thing.

We have plenty of other customers with an SBX, with even older software, without issues either.

This customer had the original 4000-00 BKSU, and our was a newer 4000-03. Sent the cabinet out to Aztec and they did a couple IC/transistor upgrades but the problem remained when it came back.

[quote=CMM...but we could duplicate the sound on the buttset. [/quote]

I'm confused. If you can duplicate the problem with your buttset, why go any further?

That's where we initially stopped and pointed our fingers at the line service. Then the whole thing with the single line phone, swapping the cabinet and other SBX cabinets/DX systems have no issues points more to the equipment.

I'm still not 100% convinced it's the equipment because our in-house system worked fine for a couple weeks, and suddenly it started happening at the customer location.

If Vertical would be more willing to work on this issue, I bet we could narrow down to a component that could be the cause, but they are just as tunnel visioned on this issue as Comcast. May end up having to port their lines back to Verizon...

Figured I'd try the boards to see if anyone saw this in their travels or had other steps to try.

Well, I don't blame Vertical for not wanting to work on it. If the KSU worked fine with the Verizon lines, and you can duplicate the issue with your buttset, the problem is clearly with the Comcast service.

A buttset should be the standard, not some cheap phone.

Kudos for trying to get this fixed, but it lies on the carrier.

You have no idea how many hours I put into proving a specific model of channel bank from a certain carrier would cause this. Put in a different model and the problem went away. Carrier complains because the channel bank that works is more expensive. Arghhh.

I had a similar situation as Dave (RBF). A few years ago, a customer changed to Comcast and their VoIP networking would constantly fail. Thankfully, the Comcast tech was willing to try installing their previous model and the problem went away. I no longer remember which models they both were but everyone was pointing fingers at each other. I was fit to be tied.

Thanks for chiming in fellas. It certainly is an uphill battle that we're fighting and it's quickly becoming more costly than necessary. This one is probably better to admit defeat and switch their services back to Verizon and hope this problem goes away for good.

Its a channel bank issue....problem is answer supervision is not set correctly...it is the opposite of disconnect supervision which is also a problem when service comes from a channel bank. It can make voice mail messages very long even when the caller hung up at the prompt.

The channel bank is too slow to notice the off hook condition of the line. I get that around here sometimes with Cox...but it is very short, about half a ring burst. Still it irritates my customers. Another reason why I prefer PRIs now...even frac ones over "POTS" lines.