Enable transcoding to/from GSM?

I configured a soft phone to use gsm, and I specified gsm as one of the codecs supported by SIP phones. But when I try to make a call from a channel using slin (aka L16), asterisk writes warnings that it cannot convert from sln to gsm; the verbatim messages are:

Unable to find a codec translation path from (slin) to (gsm) Asked to transmit frame type gsm, while native formats is (slin) read/write = slin/slin Codec mismatch on channel <foo>;1 setting write format to gsm from slin native formats (slin)
FWIW, there is no problem when I configure the softphone to use PCMU rather than GSM.

The menuselect configuration tool shows that I have codec_gsm is disabled because it depends on gsm(E), which I have not been able to figure out how to create.

If there is existing doc or a forum entry that describes how to do this, please point me to it.


Try apt-get install libgsm1-dev, then re-run ./configure in your Asterisk source directory.

Worked like a charm. Thanks! :smiley:

(Folks on Redhat descendants make the obvious change from appt-get to yum. For CentOS, there is indeed a standard gsm-devel package.)

Yay :smile: