sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Faxing and PRI issues

Dig deep and research the VoIP circuit idea. It will take calls to Verizon and their techs to find out, but check that out. As Ed and I said, VoIP soft switch driven PRI's do not play well with long faxes.

Make sure it is a regular PRI and not being provided over a VoIP soft switch or delivered VoIP. There should be a name for the service, but I am not sure of what it is; for example, Nuvox calls their VoIP circuits Vox IP and their regular ones Flexlink....

Steve

Had same problem with Dynamic PRI from Cebeyond.
Workrd for a year then stopped. Time slips, very small. After much gnashing of teeth, Cebeyond resolved on their end. On Panasonic TDA the only other indication was that the wireless Cell stations, some of them would go in and out of service every 60 seconds. We changed out the unit cards and all. Still no fix. 3 days later went on site , called TS again and got a new guy, explained problem and he fixed in 15 min. This was on a Cisco IAD.

We mostly use Cebeyond or Logix dynamic PRI. They mostly have no problems with fax, on MICS, BCM Or Panasonic.

:toast: :toast:

Are they long distance faxes or local, some carriers use a soft switch for LD calls, also if they are LD it could be one of the LD providers your carrier is using. I won't name any names but there are some LD carriers that are always problems.
If they are international calls, that's a whole new ball game and much less likely to be resolved if the call failure occurs after a handoff overseas...especially to countries with poor infrastructure.

Are they pulling the call records? Which end is disconnecting the call?

I've had similar experiences with various providers and different CPE. It was always the result of misconfiguration by the telco, I attribute this to the fact that TDMoIP (dynamic T1/PRI's prefered mode of transport) is relatively recent technology, and everybody on the provider side kinda rushed to offer it, maybe wthout having the proper infrastructure in place (this includes expertise).
Now if the problem is the existence of some softswitch down the line, I think little can be done other than pressing the telco to own up to it or changing to a provider who's more forthcoming with the way signals move through their network - so at least you know the path your comms follow end-to-end, or at least until the leave the telco's net.

All I can tell you is that I had this exact problem with calls that were going into a fax server on a PRI through a Mitel 200 ICP. As soon as I set it up in auto mode (dual clocking) instead of free run (clocking off the network) all the problems went away - did this at a suggestion from a friend because the signal strength on the PRI circuit was a bit low.

I will second ( or 3rd or 4th) the opinion that its probably an IP circuit converted to a PRI.

Are you sharing the same T1 for data and voice? Does a single T1 come in and break out into voice PRI and data T1?

Some of the circuits will work fine for faxing if the carrier uses something called t.38. I won't butcher the technical explanation but it converts the time-sensitive scanlines into encapsulated packets of fax data and sends them to the other end to be converted back to fax data. Reduces the chances of audio loss.