[asterisk-users] Phones cutting out.....again - PLEASE HELP!!!

[whois wes]

Hate to drag this one back up, but....it's happening again.

Overview of architecture:

Dell poweredge 2850, running fedora core 4, asterisk 1.2.7.1, zaptel
1.2.5, and sangoma wanpipe 2.3.4 drivers. T1 interface card is the
sangoma a104d with onboard echo can.

Server is located in our data center and connected directly to our
cisco 6513 core switch, so we have almost zero latency. The office
having the issues is located several miles away and is connected via a
10Mbit fiber pipe, also low latency. Ping times between remote office
and here are well under 10ms.

T1's are robbed-bit, E&M wink signalling <--- (this may be cause, but
want your input).

Server load is averaging around 20%, plenty of memory, disk space, and
bandwidth available. No QOS running on network. ulaw is the primary
codec.  Server is stable, and there are no extraneous services
running, save mysql and httpd.  Even running a processor intensive
query doesn't trigger the droputs, they happen randomly.

Phones are a mix of Eyebeam 1.5.5 and Eyebeam 1.10 3010n. Both types
of phones are experiencing cutting out of the signal, mainly in the Rx
stream, but occassional in the Tx stream as well. The cutting out was
NOT occurring last night, and the phone server is being rebooted
nightly.  Nothing has changed AT ALL, and the problem has started
occurring again.  If I don't do ANYTHING at all today, there is a 50%
chance that this will NOT occur tomorrow.  In other words, SOMETHING
is causing our phones to drop out, but whatever changes I make seem to
have no effect.  The problem will start and stop seeminly at it's own
whim.

---
Things I have tried:

1.  changed from ulaw to gsm as primary codec - no change
2.  disabled hardware echo can on A104D - no change
3.  moved from asterisk 1.2.4 to 1.2.7.1, recompiled both several
times - no change
4.  have played with gain settings a bit, doesn't seem to make much difference
---

At this point, i am nearing the end of my rope - i have rebuilt this
machine three times now, and have recompiled the system at least a
dozen times. We have gone from Digium hardware to Sangoma harware and
back again. I have changed every conceivable setting on the phones to
no avail. The problem will randomly disappear, only to come back a few
days later. I can make a change, it seems to have an effect, then
we're back to the same old thing again.

I am in dire need of ANY help anyone can offer, this has been going on
in some form for almost three months.

Thanks for reading,

Wes