Getting started with DAHDI / Asterisk: "dahdi show channels" shows nothing

Asterisk Asterisk Hardware
1

I am trying to get DAHDI and Asterisk working with a Digium A4A card, 4 x FXO modules. The eventual goal is to have 4 incoming PSTN lines and an IVR system. No internal extensions and no dialing out required.

DAHDI starts but “dahdi show channels” shows no channels. I do not know whether this is due to a hardware or setup problem, or due to a problem with my configuration files.

Thanks to help from this forum thread:

I have got around the “init.d/dahdi start script does not exist” problem and got DAHDI to start.

Being new to Asterisk I don’t fully understand what I’m doing here, but I have attempted to set up chan_dahdi.conf and extensions.conf as indicated in the A4A card manual:

lsmod shows that dahdi is loaded; “dahdi show version” and “dahdi show status” appear to confirm this.

$ lsmod ! grep dahdi
dahdi_transcode 14291 1 wctc4xxp
dahdi_voicebus 59241 2 wctdm24xxp,wcte12xp
dahdi 228088 19 xpp,wctdm24xxp,wcaxx,wcfxo,wctdm,dahdi_transcode,oct612x,dahdi_voicebus,wcb4xxp,wct1xxp,wct4xxp,wcte43x,wcte11xp,wcte12xp,wcte13xp
crc_ccitt 12707 2 wctdm24xxp,dahdi

$ dmesg | egrep ‘dahdi|wcaxx’
[ 31.172824] dahdi: loading out-of-tree module taints kernel.
[ 31.173844] dahdi: module verification failed: signature and/or required key missing - tainting kernel
[ 31.175857] dahdi: Version: 2.11.1
[ 31.176303] dahdi: Telephony Interface Registered on major 196
[ 34.331291] wcaxx 0000:03:02.0: Firmware version: a0017
[ 34.435583] wcaxx 0000:03:02.0: Echo cancellation for 4 channels
[ 35.381058] wcaxx 0000:03:02.0: VPM450: Present and operational servicing 1 span
[ 38.499236] wcaxx 0000:03:02.0: Port 1: Installed – AUTO FXO (FCC mode)
[ 38.499243] wcaxx 0000:03:02.0: Port 2: Installed – AUTO FXO (FCC mode)
[ 38.499247] wcaxx 0000:03:02.0: Port 3: Installed – AUTO FXO (FCC mode)
[ 38.499251] wcaxx 0000:03:02.0: Port 4: Installed – AUTO FXO (FCC mode)
[ 38.501356] wcaxx 0000:03:02.0: Found a Wildcard A4A (SN: 1A4A00F - DM41140100239 - A - 20131212)
[ 38.878990] dahdi_transcode: Loaded.
[ 40.365625] dahdi_devices pci:0000:03:02.0: local span 1 is already assigned span 1

CLI> dahdi show version
DAHDI Version: 2.11.1 Echo Canceller: HWEC

CLI> dahdi show status
Description Alarms IRQ bpviol CRC Fra Codi Options LBO
Wildcard A4A OK 6 0 0 CAS Unk 0 db (CSU)/0-133 feet (DSX-1)

However, “dahdi show channels” shows nothing. Since wcaxx is detecting the 4 x FCO ports I suspect the installation and setup might now be OK, and the problem might be in my .conf files. Would appreciate confirmation that I might be on the right track.

CLI> dahdi show channels
Chan Extension Context Language MOH Interpret Blocked In Service Description
pseudo default default Yes

Asterisk 15.4.1
DAHDI 12.1.1
CentOS Linux 7 (Core) kernel 3.10.0-862.3.3.el7.x86_64

2

Additional info:

In /etc/dahdi/system.conf I changed loadzone and defaultzone from “us” to “uk” since that’s where I am. Since I have 4 x FXO modules I have “fxsks = 1,2,3,4”.

Then in /etc/asterisk/chan_dahdi.com I have (at the end):

;FXO Modules
group = 1
echocancel = yes
signalling = fxs_ks
context = Incoming
channel = 1-4

It would be nice to know if there is anything obvious that I’ve done wrong so far.

3

Support for configuring hardware cards is provided by the vendor (DIgium), not by the open source community. You will need the card serial number when contacting Digium.

4

Never mind, I seem to have got it working now. The solution was, to ignore the 2 lines in the chan_dahdi.conf in the O’Reilly book (4th edition, p. 117) that say

; The channels context is used when defining channels using the
; older deprecated method. Don’t use this as a section name.

In other words, I moved the relevant config commands from the “phone” section to the “channels” section.