[Asterisk-Users] FAX, IAX and *....Maybe I'm dreaming...:-)

[ProvoCityPower]

> ----- Original Message ----- 
> From: "Alastair Maw" <asterisk at almaw.com>
> To: <asterisk-users at lists.digium.com>
> 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.

The question asked here, "why on earth you want to push fax data over a VoIP link at
all. Fax compression isn't very efficient." may speak volumes about the future role of VOIP. My plans are to role out a VOIP connection to thousands of Customers. Many have legacy fax equipment. Am I to assume that they will toss out their fax equipment and join the PC based faxing crowd? I don't think I can control this. If I am going to offer an aternative to the legacy wire providers then I have to offer a comparable service. One that for example allows a customer to use a legacy fax machine in the same way.

If this thought sidetracks the intent of this thread, you have my apologies, but I do think that legacy fax functionality is essential.

Jeff

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20031214/6ca9cec3/attachment.htm