[asterisk-dev] fallback to audio faxing when T.38 INVITE fail with 488/606 Not acceptable

[Kevin P. Fleming]

Kristijan Vrban wrote:
> Hello, i use 1.4 asterisk (1.4.28 and svn) to make T.38 passthrough
> between a Siemens hiQ9200 (british telecom) and an asterisk 1.6.2 with
> app_fax/spandsp as T.38 termination endpoint.
> this is working. But in the case that the hiQ9200 reply our T.38
> INVITE with a  606 Not Acceptable, the 1.4 asterisk just hangup up,
> and does not ACK this reply to fallback to audio faxing.

6xx response codes are fatal responses; the call must be terminated when
one is received. The proper response for a endpoint that wishes to
refuse a T.38 re-INVITE is a 488.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kpfleming at digium.com
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