[ale] Hylafax and Vonage

[James P. Kinney III]

On Wed, 2005-01-19 at 20:59 -0500, Steven A. DuChene wrote:
> OK, I have been thinking about this today and I am just confused.
> Vonage is by definition a VOIP phone service with zero depeandancy
> on a physical POTS line. Faxing & Hylafax are by definition services
> that deal with faxes occuring across a actual hardwired POTS line
> and a regular dial-up modem. Now once the system running Hylafax
> picks up the modem line and accepts the fax there may be some IP
> traffic but other than that I am just puzzled how a VOIP service could
> be affecting or even interacting with a fax modem that should unless
> I am misunderstanding things be connected to a POTS line.

It's a sampling problem. VOIP does not sample voice at the same rate as
the POTS line does. Running an all-analogue device over a digital
carrier can "look" like watching a pc monitor that was taped by a video
camera. It just doesn't sync up right. Running analogue fax over VOIP
like Vonage (and CBeyond where I first ran into this problem) requires a
sample rate compatible with fax data rates. Some integer multiple of fax
speed is required or else there is frame drops and/or broken frame data
fields. On the far end of this there is now a very confused fax machine.

Voice data over the fax line will sound different using VOIP. POTS
doesn't care since it's all the same stuff to it.
> 
> -----Original Message-----
> From: Brandon Colbert <brandon at geekrus.net>
> Sent: Jan 19, 2005 5:12 PM
> To: Atlanta Linux Enthusiasts <ale at ale.org>
> Subject: [ale] Hylafax and Vonage
> 
> Upon switching to Vonage, we have lost the ability to connect with
> many of our clients.  30-40% of incoming faxes don't complete and
> about the same number of outgoing ones do not complete.
> Are there any special settings in hylafax to get it to work correctly over VOIP?
> 
> 
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> !DSPAM:41ef10ab4396701269097!
-- 
James P. Kinney III          \Changing the mobile computing world/
CEO & Director of Engineering \          one Linux user         /
Local Net Solutions,LLC        \           at a time.          /
770-493-8244                    \.___________________________./
http://www.localnetsolutions.com

GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
<jkinney at localnetsolutions.com>
Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7
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