asterisk users - Dec 2009 - "Dropping incompatible voice frame" error

I have a SIP phone calling an AGI application.  It starts out this way:

    -- Executing [s at macro-Call-AGI:2] AGI("SIP/151-b414f0c8",
"computer-temp.sh,darwin,") in new stack
    -- Launched AGI Script /var/lib/asterisk/agi-bin/computer-temp.sh

Then I get a dozen or so copies of:

[Nov 30 22:40:03] NOTICE[28300]: channel.c:2962 __ast_read: Dropping
incompatible voice frame on SIP/151-b414f0c8 of format ulaw since our native
format has changed to 0x2 (gsm)

and then it's fine:

    -- Playing '/var/lib/asterisk/agi-bin/machine_darwin_prefix'
(escape_digits=) (sample_offset 0)
    -- AGI Script Executing Application: (Playback) Options:
(/tmp/say_agi28305.2)
    -- <SIP/151-b414f0c8> Playing '/tmp/say_agi28305.2.ulaw'
(language 'en')

Searching for that error on the web produces stuff that looks
unrelated.  Does anybody know what could be going on here?

Richard Kenner wrote:
> I have a SIP phone calling an AGI application.  It starts out this way:
> 
>     -- Executing [s at macro-Call-AGI:2] AGI("SIP/151-b414f0c8",
"computer-temp.sh,darwin,") in new stack
>     -- Launched AGI Script /var/lib/asterisk/agi-bin/computer-temp.sh
> 
> Then I get a dozen or so copies of:
> 
> [Nov 30 22:40:03] NOTICE[28300]: channel.c:2962 __ast_read: Dropping
incompatible voice frame on SIP/151-b414f0c8 of format ulaw since our native
format has changed to 0x2 (gsm)
> 
> and then it's fine:
> 
>     -- Playing '/var/lib/asterisk/agi-bin/machine_darwin_prefix'
(escape_digits=) (sample_offset 0)
>     -- AGI Script Executing Application: (Playback) Options:
(/tmp/say_agi28305.2)
>     -- <SIP/151-b414f0c8> Playing '/tmp/say_agi28305.2.ulaw'
(language 'en')
> 
> Searching for that error on the web produces stuff that looks
> unrelated.  Does anybody know what could be going on here?
What version of Asterisk are you running? This sounds similar to an issue with 
AGI's I saw a while ago, but I can't quite remember exactly what the
issue (or
issue number) was. Updating to the latest version from subversion in the 1.4 (or
whatever other branch you're using) may help.

Leif Madsen.