[Asterisk-Users] Problem with T1 installation

[Michael Collins]

> Nitin Joshi wrote:
> > Hi All,
> >
> > I have installed a Digium TE110P card on an Asterisk 1.2.1 system.
Its
> > connected directly to the PSTN. But I am unable to make outbound
calls
> > on the zap channels. The light on the card is green. Asterisk CLI
> > shows all 24 channels when I give the command 'zap show channels'. I
> > also noticed that Asterisk CLI shows an incoming call every few
> > seconds on the 24th channel. This must be some kind of a timing
> > signal. This is he first time I am configuring a T1 so I must have
> > done something wrong I guess.
> 
> T1s require a D (Data) channel, unless connecting to a channel bank,
It
> should be 23 voice 1 data.  Also, I would strongly suggest moving to
1.2.4
> 
> Doug

Guys,

A T1 is a T1: 24 channels in the US.  A PRI is a service that runs on
top of a T1, that is, it uses all 24 channels, but it uses a specific
channel (usually the 24th channel) for signaling.

It sounds very much like Nitin has a PRI - the 24th channel is seeing
lots of activity which is a pretty good sign of a PRI, but not always.
It could be a regular incoming call on the 24th channel of a standard
digital trunk, sometimes called a "supertrunk" by some carriers.

Nitin, can you confirm with your telecom carrier that you do indeed have
a PRI?  You need to ask them if it is a PRI circuit or a standard
24-channel digital trunk.  It looks like the framing and coding are
correct: B8ZS and ESF, which are typical for both PRI's and digital
trunks.  Finally, if it is a PRI then you'll need to know what switch
type they use: National, 4ess, 5ess, DMS100, etc.  Some carriers call
this the "protocol variant."  

Here's a sample of a zaptel.conf for my PRI here in California (Qwest):

loadzone	= us
defaultzone	= us
span=1,1,0,esf,b8zs # My PRI line
bchan=1-23
dchan=24


Here is a sample zapata.conf with PRI, where the switch type is 5ess:

[channels]
language=en
context=from-pstn
signalling=pri_cpe
switchtype=5ess
rxwink=300		; Atlas seems to use long (250ms) winks
callerid=asreceived
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=yes
echotraining=400
rxgain=0.0
txgain=0.0
group=0
callgroup=1
pickupgroup=1
immediate=no
channel => 1-23

Save your existing zaptel and zapata conf files and try playing with
these settings.  You might just figure it out without calling the telco,
although if you spend more than 15 minutes tinkering you're probably in
need of telco's assistance.

-MC