Hi, ----- Original Message ----- From: "Alastair Maw" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, December 12, 2003 4:58 PM Subject: Re: [Asterisk-Users] FAX, IAX and *....Maybe I'm dreaming...:-)
> On 12/12/03 13:56, Dan wrote: > > This is because the fax is transmitted using the audio stream. > > It is not related to the signaling protocol (SIP/IAX etc.) but to the audio > > codec used. > > Fax uses FSK modulation to transmit the data. If you compress this in a > lossy way (GSM, MP3, whatever) then the integrity of the data is > affected (more or less seriously depending on the codec used). Fax > machines are generally quite picky, so compressing faxes is unlikely to > work. > > I'm wondering why on earth you want to push fax data over a VoIP link at > all. Fax compression isn't very efficient. Who wants that??? By fax data I mean the data contained in a fax (basically a picture file), not the fax data audio stream. It can be converted (GIF or JPG) then sent reliable over a slow IP link. Just a special codec at both ends, able to pass the data to the fax app or a fax machine connected to a TDM400/ AT or whatever. > It would be much less > bandwidth intensive to decode the fax and send it over as proper data > rather than audio, compressed using gzip/gif/png/something else. This is exactly what would be great to have it. BR, Dan _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users
