[asterisk-users] "Dropping incompatible voice frame" error

[Richard Kenner]

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?