On 08/05/2011 07:51 PM, Kevin P. Fleming wrote: > On 08/05/2011 12:06 PM, Robert Thomas wrote: > >> I'm refering to the audio hook implemented to the detect the V21 >> preamble fax on the T38 gateway implementation on asterisk 1.10. >> >> I think it depens whether they refer to fax detection to disable echo >> cancellation, or to renegotiate to T38. > > Neither. In most cases, 'FAX detection' in Asterisk used to to > redirect the channel to a different extension in the dialplan. This is > done by detecting CNG, so that the destination of the call can be > changed to one that is able to handle the FAX transaction. Asterisk > does not handle echo canceller reconfiguration for FAX at all; that's > done by DAHDI or the echo cancellers themselves. Hi, I've been using the asterisk 1.6.X. Here asterisk can only detect fax tones with chan_dahdi. chan_ss7, sip and iax do not detect fax tones and therefore do not forward the call to the fax extension. I see mention of NVfaxdetect on the Internet, but it looks like this code is no longer maintained. I've just taken a look at chan_sip in 1.8.5, and it looks like 1.8.5 can detect fax tones on sip channels. Will test this out later. Asterisk 10 is still beta, and not suitable for production - but good for testing. A.
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