[Asterisk-Users] UK ISDN PRI Problems

[Chris Barnett]

Advance apologies for the length of this mail;

I have an ISDN PRI supplied by NTL (ex Diamond Cable, Nottingham) which
is currently working happily with an SDX Index phone system. I have to
replace this phone system shortly and I've been trying to get a * system
working for some weeks now. I have configured the dial plan (which
works) and all my SIP extensions (which all work) along with voice mail
etc. etc. - all this works perfectly as an internal PBX. My problem
comes when I try to connect it to my ISDN line.

I have a Digium E100p card which is configured in zaptel.conf thus;

span=1,0,5,ccs,hdb3,crc4
bchan=1-15
dchan=16
bchan=17-31
loadzone=uk
defaultzone=uk

The zapata.conf is like this;

[channels]
usecallerid=yes
callerid=asreceived
hidecallerid=no
threewaycalling=yes
transfer=yes
cancelforward=yes
callreturn=yes
immediate=no
callprogress=no
language=en
echotraining=yes
echocancel=yes
echocancelwhenbridged=yes
rxgain=-5%
txgain=+5%
pridialplan=unknown
overlapdial=yes
signalling=pri_cpe
switchtype=euroisdn
context=inboundpstn
group=1
channel => 1-15
callgroup=1
pickupgroup=1

Whenever I try to connect this up to the ISDN line I get a series of Red
Alerts and any attempt at outgoing calls results in a no channels
available message (essentially all the lines are shown in use and cannot
be cleared). I have had my teleco reset the line which just results in
further red alerts. NTL, bless them, came out with a test rig and
plugged this in the back of my * box and we made a series of test calls
which all worked fine, although the NTL chap said the attenuation was
out as there was a lot of buzz on the line. He suggested we set the line
build out to 6 (-15db) but we were still getting buzz on the test calls
- other than that he was happy that the config was correct and as the
test rig showed the * box talking properly and making outgoing calls OK
we all reckoned that the next time we hooked up to the ISDN line it
would be OK. I couldn't do this with him there as the system is in use
during the day, so had to wait until the evening after he'd gone.

However, I still get the red alerts. If I leave the * box connected to
the ISDN line when the teleco attempt to reset the line it immediately
trips with another series of red alerts, however it resets just fine
when plugged back into the SDX Index system. The teleco says they can
see it tripping, but don't know why (?).

I have made sure that the card is not sharing interrupts and I've
scoured the mail archives and google for any further information I can
get my hands on. I just can't get past the red alerts.

Does anyone on the list have any idea why this is happening (big
question I know), I'm using the stable CVS tree from 15/4/04. Is there
anyone else out there using * with an NTL ISDN PRI line?

Many thanks for any help offered :)

Chris Barnett