[Freeswitch-users] send fax via google voice.

[Ken Rice]

Ok
1. will sending a fax over it work... The answer is yes it will work..
2. will it work reliably, no
Faxing just needs to die already...
The problem you have here with Faxing over G711 (PCMU or PCMA) is that
faxing uses a modem to encode a digital signal into an analog carrier meant
for a circuit switch voice network with a constant amount of delay and
guaranteed delivery of the entire analog stream

VoIP by definition is Voice Over Internet Protocol... IP is a packet
switched network, where you can no guarantee a constant amount delay
(latency) ... Not to mention it is not common to see a udp packet or 2
missing along the way.

Where as 1 20ms packet may not seem like much to you, that¹s roughtly
equivalent to 575bytes of data in the fax and it will screw up the fax
either causing a corruption of the data, or a drop in the analog modem
carrier which requires a retrain...




On 3/5/11 11:35 PM, "envelopes envelopes" <sunwood360 at gmail.com> wrote:

> ok,  
> 
> Reliability is a different issue. I am just wondering whether mod_dingaling
> supports fax via GV. because someone proved sending fax via GV from fax
> machine did work
> .(http://www.magicjacksupport.com/faxing-via-google-voice-t7412.html).
> 
> 
> 
> On Sat, Mar 5, 2011 at 9:18 PM, curriegrad2004 <curriegrad2004 at gmail.com>
> wrote:
>> And relativity comes into play too.
>> 
>> Also you do need to realize that the packets sent via UDP isn't
>> guaranteed to be in order as the fax machine expects the data to be
>> sent in order, not out of order. That's the beauty of packet switched
>> networks.
>> 
>> On Sat, Mar 5, 2011 at 7:29 PM, Steve Underwood <steveu at coppice.org> wrote:
>>> > On 03/06/2011 11:21 AM, envelopes envelopes wrote:
>>>> >>
>>>> >> Why is PCMU codec not reliable?
>>>> >>
>>>> >>
>>> > Unsynchronised clocks, and packet loss.
>>> >
>>> > Steve
>>> >
>>> >
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>> 
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