Question about VOIP and Faxes

[geoffrey mendelson]

On Jan 21, 2010, at 12:48 PM, Boris shtrasman wrote:

>
>
> Just a question  (Since I truly don't know enough about the  
> subject ) -
> How does it work ? since afaik there are bandwidth issues .
> (plus the charge started after the sync) - so using VoIP may be  
> problematic at best.



To oversimplify it, fax uses a simple I send you a data packet and you  
send me an ack protocol.  It's designed for sending data over a POTS  
line, without a lot of tollerance for dropped, late or mangled  
packets. The latest standard, which is still changing, T-38 allows for  
faxes to be sent over VoIP, but it is not (yet) reliable.

The other problem is that fax machines need to have the ability to  
accept the problems of faxing over VoIP, such as late acks, etc. Most  
don't.

 From what I have seen the much more reliable fax over TCP nor the  
relaxed timing and robustness options do not exist in generally  
available (ok, cheap) fax machines, instead they have a "fax over  
email"  or "scan and email" button, and include  support for it in  
their Windows drivers.

Geoff.

-- 
geoffrey mendelson N3OWJ/4X1GM
Jerusalem Israel geoffreymendelson at gmail.com
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge  
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