DAHDI transcoding

[wimnat]

I have a box with a TDM410P card with 3 FXS ports. It’s installed and is working fine. I can receive calls in Asterisk and do to them as I wish in my dialplan. One wish is to forward the call over an IAX trunk to another Asterisk box and then dial a SIP phone at the other end.

Some times the call is placed over the trunk but when I pick up at the other end there is nothing but a loud horrible buzzing, distorted sound. When this happens I get this in my logs…

[Mar 24 03:11:54] VERBOSE[2245] logger.c: – Called au-uk-iax/27458@iaxtosip
[Mar 24 03:11:55] VERBOSE[2186] logger.c: – Call accepted by 203.38.242.116 (format g729)
[Mar 24 03:11:55] VERBOSE[2186] logger.c: – Format for call is g729
[Mar 24 03:11:55] WARNING[2186] channel.c: Unable to find a codec translation path from 0x100 (g729) to 0x8 (alaw)
[Mar 24 03:11:55] WARNING[2186] channel.c: Unable to find a codec translation path from 0x100 (g729) to 0x4 (ulaw)
[Mar 24 03:11:55] VERBOSE[2245] logger.c: – IAX2/au-uk-iax-16384 answered DAHDI/1-1
[Mar 24 03:11:56] WARNING[2192] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2184] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2185] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2186] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2187] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2188] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2189] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2190] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2191] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2192] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2193] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:56] WARNING[2184] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2185] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2186] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2187] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2188] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2189] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2190] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2193] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2184] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2185] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2186] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2189] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2190] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2191] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2192] chan_iax2.c: Received trunked frame before first full voice frame
[Mar 24 03:11:57] WARNING[2185] channel.c: Unable to find a codec translation path from 0x100 (g729) to 0x4 (ulaw)
[Mar 24 03:12:43] VERBOSE[2245] logger.c: – Hungup ‘IAX2/au-uk-iax-16384’

Other times the call doesn’t even make it and I see this in my logs…

WARNING[2534] chan_iax2.c: Unable to create translator path for unknown to ulaw on IAX2/au-uk-ia
x-16384

I think it all stems from this error which I always get at startup…

VERBOSE[13590] logger.c: == Parsing ‘/etc/asterisk/codecs.conf’: [Mar 24 04:32:06] VERBOSE[135
90] logger.c: == Found
[Mar 24 04:32:06] VERBOSE[13590] logger.c: – codec_dahdi: using generic PLC
[Mar 24 04:32:06] ERROR[13590] codec_dahdi.c: Failed to open /dev/dahdi/transcode: No such file or directory
[Mar 24 04:32:06] VERBOSE[13590] logger.c: codec_dahdi.so => (ESC[33;40mGeneric DAHDI Transcoder Codec Translator
ESC[0;37;40m)

Does anyone have any ideas about how I can fix this?

[wimnat]

bump

[jrleach]

Have you loaded the dahdi_transcode kernel module?

try lsmod to verify its loaded

[wimnat]

No, but I didn’t want to call it explicitly because I didn’t think that was the way to do it. I thought it would of been loaded by the dahdi module or something.

Is the call supposed to be explicit?

[wimnat]

Update:

Loaded dahdi_transcode through a simple modprobe call in /etc/rc.modules.

/var/log/messages
Mar 30 00:43:01 mirror kernel: dahdi: Telephony Interface Registered on major 196
Mar 30 00:43:01 mirror kernel: dahdi: Version: 2.1.0.4
Mar 30 00:43:01 mirror kernel: dahdi_transcode: Loaded.
Mar 30 00:43:07 mirror kernel: Port 1: Installed -- AUTO FXO (UK mode)
Mar 30 00:43:08 mirror kernel: Port 2: Installed -- AUTO FXO (UK mode)
Mar 30 00:43:08 mirror kernel: Port 3: Installed -- AUTO FXO (UK mode)
Mar 30 00:43:09 mirror kernel: Port 4: Not installed
Mar 30 00:43:09 mirror kernel: Found a Wildcard TDM: Wildcard TDM410P (4 modules)
Mar 30 00:43:09 mirror kernel: dahdi_echocan_mg2: Registered echo canceler 'MG2'
Mar 30 00:43:09 mirror kernel: dahdi: Registered tone zone 4 (United Kingdom)

So, that looks all OK to me. Here’s my lsmod

lsmod | grep dahdi
dahdi_echocan_mg2       9608  0
dahdi_transcode        12168  0
dahdi                 190728  12 dahdi_echocan_mg2, wctdm,wctdm24xxp, dahdi_transcode
crc_ccitt               6337  1 dahdi

Then in the Asterisk console the command ‘transcoder show’

mirror*CLI> transcoder show
No DAHDI transcoders found.

[wimnat]

bump