Asterisk configuration and troubles with Fastweb ISDN

At the moment I’m configuring an asterisk PBX trying to make it work with Fastweb ISDN lines (I’m in Italy). It’s been a headache so far and I found few structured articles online so I hope this can be of help to others as well as me in the future.

First of all my environment:

  • I have 4 BRI ISDN lines with fastweb,
  • at the moment I have 3 BRI ISDN lines with telecom Italia with numbers that are going to be ported to fastweb,
  • every Telecon Italia BRI as 1 number associated to a different company,
  • I have 8 Fastweb phone numbers (4 for every BRI) and soon 2 more numbers ported from telecom italia to fastweb (I’m not porting the third number),
  • I have a desktop computer HP which I’m going to use as a server,
  • I bought a Openvox BE400E BRI card which has hardware echo cancellation and support 4 BRI channels,
  • I bought several gigaset IP/DECT phones which I’m going to configure (another article) to use with the PBX,
  • I bought a IP Phone to use as the main system phone in the reception.

I decided to go for an easy installation with Asterisknow.

Initially I went for a FreePBX GUI setup but in a later installation I switched to the asterisk GUI because the first is storing the configuration in an internal DB while the latter is using the canonical configuration files.

Unfortunately the latter is why bugger… I’m going to have to live with it…

The configuration for the openvox can be found here (for the DAHDI):

it is not well written but the step are easy (I’m chaning it for asterisk now):

  • install the asterisknow,
  • update the asterisk configuration to 1.8 with the command: yum update –enablerepo=asterisk-1.8
  • install the last version of libri or at least the libpri-
  • in the step 4 of the openvox wiki the “include dahdi-channels.conf” should be “#include dahdi-channels.conf”

The hardware was configured with:

signalling = bri_cpe_ptmp

i.e. BRI point-multi-point.

Here an excerpt from my dahdi-channels.conf:

; Span 1: B4/0/1 “B4XXP (PCI) Card 0 Span 1” AMI/CCS
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 1-2
context = default
group = 63

Then my problem started.

I connected a gigaset phone to the network and a soft-phone. I was able to call internally but not externally.

The outgoing calls gave me the error:

chan_dahdi.c: dahdi_pri_error: 1 Unable to receive TEI from network!

which I thougt was do to a libpri bug. I installed and reinstalled several time my machine and several version/combinations of asterisk and libpri with no luck.

On the console the command:

[root@centralino ~]# asterisk -rvvvvvvvvvvvvvvvvvv
Asterisk, Copyright (C) 1999 – 2011 Digium, Inc. and others.
Created by Mark Spencer <>
Asterisk comes with ABSOLUTELY NO WARRANTY; type ‘core show warranty’ for details.
This is free software, with components licensed under the GNU General Public
License version 2 and other licenses; you are welcome to redistribute it under
certain conditions. Type ‘core show license’ for details.
  == Parsing ‘/etc/asterisk/asterisk.conf’:   == Found
  == Parsing ‘/etc/asterisk/extconfig.conf’:   == Found
Connected to Asterisk currently running on centralino (pid = 9059)
Verbosity was 3 and is now 18
centralino*CLI> pri show spans
PRI span 1/0: Down, Active
PRI span 2/0: Down, Active
PRI span 3/0: Down, Active
PRI span 4/0: Down, Active

Gave me down on every span.

Every incoming call ended with a dead tone and nothing appeared on console.

I lost two days!!!!! Then a Fastweb technician appeared. Finally I discovered that lines where point-to-point while my configuration was point-to-multipoint.

The ISDN lines were switched to multipoint and magically the above error disappeared the spans went Up and I was able to make and receiving calls on 4 of the 8 numbers.

On the others 4 number I still had the dead tones and a congestion error:

dial_exec_full: Unable to create channel of type ‘DAHDI’ cause 34 – Circuit/channel congestion

I lost another half day then the Fastweb man reappeared and I discovered that the 4 numbers were not configured!!!!

Fastweb configured the number and the error was solved.

I was able to make calls and receiving them on all my numbers.

On asterisk 1.8 I’m getting:

[Jan 20 11:07:34] WARNING[9101]: db.c:115 dbinit: Unable to open Asterisk database ‘/var/lib/asterisk/astdb’: Permission denied
[Jan 20 11:07:34] WARNING[9101]: db.c:592 ast_db_gettree: Database unavailable

solved with the simple command:

chown asterisk:asterisk /var/lib/asterisk/astdb

So I summarize the installation with:

  • install asterisknow,
  • go for a vanilla configuration,
  • ensure the ISDN lines are point to multipoint,
  • ensure that the Fastweb numbers are properly configured.

More to come!!!

, ,