Weird problem - VG248 outbound calls to toll free numbers

Unanswered Question
Oct 21st, 2009


Have a weird problem that started yesterday. We have three VG248's running version 1.2(1) with a mix of fax and modems attached. These are part of our CM 4.1(3)sr6 installation, as is a 2811 router with two PRI's attached, one for local telco the other to our LD carrier. Starting yesterday, we started experiencing issues with calls made from VG248 attached devices to toll-free numbers (866, 888). Calls to local and non toll-free numbers work fine. This problem not localized to one VG248; we've seen it on two of them so far. Just to add to the confusion, some of the ports are still able to reach the toll-free numbers while others are getting the classic "Your call cannot be completed as dialed" message. ISDN Q931 Debugs on the gateway routers look almost identical between the successful and unsuccessful calls. Only difference is a "Q931: TX -> CONNECT_ACK" seen on the successful connection. Calls from 7940's & 7960's to the toll-free numbers work fine every time. We've swapped modems, tested with analog handsets and used different DN's on the analog ports without making a difference. These VG248's have been in service over 2 years without a hitch. I've asked our telco folks to talk with the carrier, but am wondering if anyone else has seen such weirdness before.



I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Paolo Bevilacqua Wed, 10/21/2009 - 09:08

Only difference is a "Q931: TX -> CONNECT_ACK"

That should be preceeded by an incoming CONNECT message. That is key. Sometime, but not always, toll free numbers do not send the CONNECT, that in some way is synonymous of billable call.

The problem is purely software, you should investigate further what makes some of your ports to behave diffrently than others.

CHRIS CHARLEBOIS Wed, 10/21/2009 - 10:30

Does the problem only occur on certain ports? Does it always occur on these ports? If you move a device from a 'bad' port to a 'good' port, does the problem follow the port?

The fact that it is getting to the gateway and you can see the q931 data makes me doubt that it's coming from the VG248's. Have you captured the q921 detailed debugs?

sysjes Wed, 10/21/2009 - 11:45

Are you using the same CSS for the analog devices as your 7940/7960?

Is the toll free going out the local PRI? On the isdn debug the destination is the same digit for digit?

bread Wed, 10/21/2009 - 13:12

Problem resolved.

The DN's for the analog ports had not had the External Phone Number Mask set, and apparently the carrier now wants that for toll-free calls. Nothing we'd ever seen before, but we're adding that setting to a few dozen DN's now.

Thanks to all for getting back to me so fast and for your input!

Paolo Bevilacqua Wed, 10/21/2009 - 13:20

No worries.

Carriers in the US are beginning to enforce calling number correctness, yes this is new.

Perhaps someone powerful complained about being called from 911 or the White House!


This Discussion