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FOIP (Fax over IP)

 
 
Theo Markettos
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      02-19-2011
Roger Burton West <(E-Mail Removed)> 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.

Theo
 
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Deborah Weiner
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      02-19-2011
On Sat, 19 Feb 2011 00:33:32 -0000, "Graham." <(E-Mail Removed)> wrote:

>
>"Deborah Weiner" <(E-Mail Removed)> wrote in message news:(E-Mail Removed)...
>>
>> 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
>> appropriate fax codecs once I have a server I want to use.
>>
>> What I need help finding is a FOIP server that can interface with a
>> SIP/VOIP connection. When I google for servers, I either come up with
>> expensive professional software meant for large businesses, or links
>> to the free fax service providers. Neither of those is good for me.
>>
>> I'm looking for a solution that a single person can use on either
>> Linux (Fedora 13) or Windows (Windows 7). I don't mind paying for the
>> software, but $1000+ commercial options are obviously not within my
>> budget.
>>
>> Deb

>
>Have you tried sending a fax over the existing hardware you are using for voice?


I realize I was inadvertently vague.

My existing voice "hardware" is my cell phone. My VOIP solution is via
soft phones clients on my cellphone and my laptop.

I'm interested in a pure software solution. What I would like to do is
send a fax over a VOIP softphone connected over wifi.

I would think "in theory" this is possible, as long as I use a
softphone with the correct codec. In practice it may not be possible.
There may not be a clear way to push the fax signal to the softphone,
instead of the physical fax-modem port on the computer.

>I occasionally send faxes via smartvoip and they seem to be received OK, I just sent
>a two page fax from Microsoft Fax with a lot of graphics to myself via a fax to email service, and I received it
>flawlessly.
>
>For the record the hardware is a Lynksys PAP2 ATA which I think is negotiating
>a G711u codec with Smartvoip. All echo cancellation is enabled incidently, if
>I had a problem sending faxes, the first thing I would do is disable those settings.
>
>The Fax to email service I use for incoming faxes is from ukddi.com, free, and a normal
>geographic number.


Someone had said to use this codec: G.711 A-Law (assuming you are not
in North America). I see from googling that A-Law is in Europe and
U-Law is in the US. I'll be backpacking through Oceana (AU, NZ, PNG)
and some parts of SE Asia for about six months. I already know I'm
going to have to do a reasonable amount of faxing. When I'm not
travelling I'm in the US and would like to use my home wifi
connection.

Deb
 
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alexd
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      02-19-2011
Meanwhile, at the uk.telecom.voip Job Justification Hearings, Deborah Weiner
chose the tried and tested strategy of:

> I'm interested in a pure software solution. What I would like to do is
> send a fax over a VOIP softphone connected over wifi.
>
> I would think "in theory" this is possible, as long as I use a
> softphone with the correct codec. In practice it may not be possible.


In some circumstances the wifi could end up being the most lossy/jittery
link in the chain, so if it doesn't work you could try connecting with an
ethernet cable instead.

> Someone had said to use this codec: G.711 A-Law (assuming you are not
> in North America). I see from googling that A-Law is in Europe and
> U-Law is in the US. I'll be backpacking through Oceana (AU, NZ, PNG)
> and some parts of SE Asia for about six months.


It's where your SIP provider breaks out to the PSTN that the codec matters
for, not where your SIP client is.

> I already know I'm going to have to do a reasonable amount of faxing. When
> I'm not travelling I'm in the US and would like to use my home wifi
> connection.


A faxing holiday? Takes all sorts, I suppose...

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Deborah Weiner
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      02-19-2011

>> I would think "in theory" this is possible, as long as I use a
>> softphone with the correct codec. In practice it may not be possible.

>
>In some circumstances the wifi could end up being the most lossy/jittery
>link in the chain, so if it doesn't work you could try connecting with an
>ethernet cable instead.


Point taken.

>> Someone had said to use this codec: G.711 A-Law (assuming you are not
>> in North America). I see from googling that A-Law is in Europe and
>> U-Law is in the US. I'll be backpacking through Oceana (AU, NZ, PNG)
>> and some parts of SE Asia for about six months.

>
>It's where your SIP provider breaks out to the PSTN that the codec matters
>for, not where your SIP client is.


Okay, well my SIP providers will all be in the US, in that case I'll
assume U-Law until I learn otherwise.

Deb
 
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Deborah Weiner
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      02-20-2011
On Thu, 17 Feb 2011 19:07:45 -0500, Deborah Weiner <(E-Mail Removed)>
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
>appropriate fax codecs once I have a server I want to use.


I made a little progress by searcing for "Fax over SIP" instead of
"Fax over VOIP".

A plugin for Microsoft Fax:
http://www.faxback.com/transfer/msFa...nDownload.aspx

Kapanga, a softphone with fax support/codecs:
http://www.kapanga.net/IP/home.cfm

Kapanga looks like it may be a bit of a sneak as the forums indicate
the fax codec needs special licensing.

I'm using Linux as my OS but I'll try them when I boot back into
Windows.

Does anyone else know of any other options to use a broadband SIP
softphone connection to send faxes that does NOT involve using a 3rd
party web/email service?

Deb
 
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David Woolley
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      02-20-2011
Deborah Weiner wrote:

>
> My existing voice "hardware" is my cell phone. My VOIP solution is via
> soft phones clients on my cellphone and my laptop.
>


I would think the chances of anything but T.38 working from a cell phone
are rather low, as you are asking for better than cellphone voice
quality, i.e. you are asking for low jitter, low delay, low loss
transmission at more than six times the GSM full rate bit rate.

Generally mobile phone companies support IP on a best effort basis,
giving priority to non-IP speech.

What I didn't mention before is that the other problem you may get with
VoIP is delay. Some modems will fail to train up initially if the delay
is excessive. I'm not sure if this applies to any fax modems, but it
was certainly of concern to BT with 21CN (which uses a VoIP backbone) as
it will prevent some older modems working on the PSTN.

Cellphones have quite a significant processing delay.

I don't know what connection quality T.38 needs. Unless it buffers
whole pages, it may suffer with poor connections, as well.
 
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Deborah Weiner
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      02-20-2011
On Sun, 20 Feb 2011 11:14:55 +0000, David Woolley
<(E-Mail Removed)> wrote:

>Deborah Weiner wrote:
>
>>
>> My existing voice "hardware" is my cell phone. My VOIP solution is via
>> soft phones clients on my cellphone and my laptop.
>>

>
>I would think the chances of anything but T.38 working from a cell phone
>are rather low, as you are asking for better than cellphone voice
>quality, i.e. you are asking for low jitter, low delay, low loss
>transmission at more than six times the GSM full rate bit rate.


I don't want to fax over my cell phone. The reason why I'm looking for
a softpfax solution is that my only "phone" line is cellular. I don't
have a POTS line.

I would like to send faxes over a SIP softphone connection installed
on my laptop. That connection will be over broadband - either DSL or
cable modem, or public wifi access points.

Deb
 
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Theo Markettos
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      02-20-2011
Deborah Weiner <(E-Mail Removed)> wrote:
> I would like to send faxes over a SIP softphone connection installed
> on my laptop. That connection will be over broadband - either DSL or
> cable modem, or public wifi access points.


Is the main reason you want to use a softphone so that you aren't tied to a
particular fax provider? I don't really see the difference between paying a
tenner (or whatever) to a VOIP provider who gives you X mins of calls and
paying the same tenner to a webfax provider who gives you Y pages of fax.
Or is there another reason?

I sometimes do quite a lot of faxing. I've tried fax over VOIP, from a fax
modem, using a fax service on the web, and an old-fashioned fax machine over
both cheap phone companies (that use VOIP for transit) and BT. The only
ones that worked reliably (to UK, Europe and Africa) were the web service,
and the fax machine on BT.

For the web service I used
http://www.popfax.com/

Not the cheapest, but it's user friendly and it works.

These days I just keep the old fax machine and drag it out for the occasions
when it's necessary, making sure I route calls via BT.

IMO messing about with fax over SIP is going to cause you a significant
amount of pain. Do you really want to spend hours retrying, telling your
callers to ring back, getting pages halfway printed before the connection
gives up, etc etc?

Now Africa is probably an extreme case (though one where fax is still
well-used) but IME fax on VOIP Just Doesn't Work. YMMV of course.

Theo
 
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Thomas Kenyon
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      02-22-2011
On 19/2/11 11:38, Theo Markettos wrote:
> Roger Burton West<(E-Mail Removed)> 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


 
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Theo Markettos
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      02-23-2011
Thomas Kenyon <(E-Mail Removed)> 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.

Theo
 
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