[asterisk-users] PRI - DS3 Calls Dropped

[bob_is_me at cox.net]

I have a customer installation with an Adtran DS3 mux. The DS1's go into my Asterisk servers that run IVR/Call recorders. The DS3 provider is Qwest, and they tell me that they routinely drop the DS3 service to redundant back-up's and that this is a common practice that happens thousands of times to DS3 lines daily across the US without any service interruptions. They say that the switchover time is covered by specification, AND my Adtran mux.

I've modified the zaptel drivers to mask out hardware alarms (alarmdebounce) with no success. I think that I have weeded out all poss ability of alarm conditions coming from the physical T1 framers, and I still get #6 and #8 HDLC PRI errors that are dropping all calls on the servers.

I've been working on this for about 6 months now, and I can't be live that all asterisk PRI installations are dropping all calls at a rate of 2 per month like I am. Everything appears to be in spec. The carrier gave me several example installations that are not dropping calls but they are not using Asterisk. They all were using my Adtran mux though. I have 3 Adtran muxes and have tried them all. I have used different T1 cards. The results are all the same. 2 times a month, all of the calls are dropped. I get a page when this happens, and then some times another from my customer who gets an e-mail about a call that was lost.

I'm starting to think that this installation is unique in its size and that this is just a byproduct of free software, but I never see this behavior in any smaller installations. 

I think that my best bet is that someone here knows how to manipulate the q931 to not drop the calls or somehow stop the errors from dropping the calls.

Thanks,
Bob