Deborah Weiner wrote:
> I'm looking for information on sending faxes on a small scale over IP.
> (FOIP). In particular I'd like to make use of one of my many SIP
> accounts to transmit the fax information. I know they need special
> codecs and I'll figure out which of my SIP accounts support the
Actually, done properly, they don't use codecs at all over the VoIP leg.
The fax data is demodulated, or never modulated, at the source, and is
sent as the raw digital stream, only being modulated if it breaks out
onto a 3.1kHz audio channel. There may be some error correction added,
I guess.
> appropriate fax codecs once I have a server I want to use.
If you are going to send fax without doing it properly, you simply need
G.711 A-Law (assuming you are not in North America) all the way to the
circuit switched network break out. The difficulty is that you need no
dropped packets and no jitter buffer re-alignments for it to work reliably.
Roger Burton West <roger+utv201102@nospam.firedrake.org> wrote:
> David Woolley wrote:
>
> >If you are going to send fax without doing it properly, you simply need
> >G.711 A-Law (assuming you are not in North America) all the way to the
> >circuit switched network break out. The difficulty is that you need no
> >dropped packets and no jitter buffer re-alignments for it to work reliably.
>
> Experience suggests that fax-over-SIP works for some people until it
> suddenly stops working for no apparent reason.
If you route through a commodity provider (eg Betamax), the routing can
change based on the phase of the moon, or whether the current time is
divisible by 3. So it works sometimes, and then doesn't work when you try a
minute later. Particularly if you're going to international destinations.
> Doing "proper" fax over IP requires T.38, but implementation seems to be
> spotty and inconsistent.
I haven't found any consumer VOIP provider that supports T.38 in any case.
Fax2email and web2fax services are probably your best bet. But you don't
get to have a portable number (as you would with SIP): if your F2E provider
stops working you need to get a new number.
On 19/2/11 11:38, Theo Markettos wrote:
> Roger Burton West<roger+utv201102@nospam.firedrake.org> wrote:
>> David Woolley wrote:
>
>> Doing "proper" fax over IP requires T.38, but implementation seems to be
>> spotty and inconsistent.
>
> I haven't found any consumer VOIP provider that supports T.38 in any case.
> http://www.t38faxing.com/ are a consumer VOIP provider that supports
(outgoing) T.38, for incoming you can use just about any fax2email
provider. (most voip providers do it nowadays)
> Fax2email and web2fax services are probably your best bet. But you don't
> get to have a portable number (as you would with SIP): if your F2E provider
> stops working you need to get a new number.
>
> Theo
Thomas Kenyon <tom@art-it-services.co.uk> wrote:
> http://www.t38faxing.com/ are a consumer VOIP provider that supports
> (outgoing) T.38, for incoming you can use just about any fax2email
> provider. (most voip providers do it nowadays)
Thanks, that's useful. It may be time to retire the fax machine...
Though T.38 is also useful for incoming calls, as it means number
portability. If your fax2email provider decides to do silly things (like
putting your faxes in a format that can only be read with a proprietary
Windows program, hint hint eFax) you can't separate the number from the
reception service. So you'd have to advertise a new number to all your
contacts.
On 23/2/11 14:35, Theo Markettos wrote:
> Thomas Kenyon<tom@art-it-services.co.uk> wrote:
>> http://www.t38faxing.com/ are a consumer VOIP provider that supports
>> (outgoing) T.38, for incoming you can use just about any fax2email
>> provider. (most voip providers do it nowadays)
>
> Thanks, that's useful. It may be time to retire the fax machine...
>
> Though T.38 is also useful for incoming calls, as it means number
> portability. If your fax2email provider decides to do silly things (like
> putting your faxes in a format that can only be read with a proprietary
> Windows program, hint hint eFax) you can't separate the number from the
> reception service. So you'd have to advertise a new number to all your
> contacts.
>
After finally getting round to playing with it, I can confirm that it
works with faxbacks T.38 plugin for Microsoft Fax.
(http://www.faxback.com/msfaxplugin/index.aspx)
I haven't tried putting asterisk in the way yet.
I did just send a 2 page fax though for what turned out to be 0.8 cents.
Re: FOIP (Fax over IP) 
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