Re: [hylafax-users] 3com / USR feedback please

["Luke McKee" <hojuruku@xxxxxxxxx>]

Andrew,

> Lee's whitepaper on VoIP is an excellent read.... it's based on both theory
> and practice;
>
> http://hylafax.sourceforge.net/docs/fax-over-voip.pdf

That's an excellent read but it only applies to non-T.38 carriers.
Thanks Lee & Andrew for that.

Speaking of which I agree that G.711u/a depends on the quality of
service. I'm going to test it with a voice service provider that is
the same as my ISP only that uses Audiocodes hardware. I've got
384kbit uplink channel. Depending on packet loss it *may* work well.
Bugger the ISP lied - it's 13 hops away peered on another network :P

Another provider that is offering a service similar to Pacific
Internet is Optus here in Australia.
Their sales people running around shop to shop door to door selling
managed PABX's with 4-8 PSTN lines to consumers touted and billed as A
REGULAR PHONE LINE!!!
On the contract it is called "Optus Voice over DSL", when really it is
"Optus Voice over IP over DSL". It's misleading as there are also
Voice over DSL protocols (AAL5) that can provide voice over an ATM
PVC.The uplink speed is 512kps even though the product literature says
the internet uplink is 64k (probably shaped at interet gateway).

The product from Optus includes internet access through the Ethernet
port in the leased DSL/router/VOIP pabx+UPS. It's also provisioned
with NAT on by default and the ISP isn't willing to configure port
forwarding. I'm helping a customer right now get out of the contract
with Optus.

With even a 9600bps ECM fax machine the local subway store is pulling
their hair out trying to receive fax orders for sandwiches! So your
concern on using the G711 codec is duly noted. So as VOIP becomes more
commonplace these issues might even occur in apparently analogue
installations. So far I haven't been able to fault the fax receiption
and transmission with hylafax in the session logs, but I believe the
customer when they complain about the reliability of the service when
it comes to faxes.

T.38 is definitely the way to go on the VOIP side of things. Depending
on voice peering if your supplier supports it *may* only work locally
or some area codes and not at all times. Usually the VOIP provider
will be able to answer these questions.

Oh yeah and there are some people who wand to fax gateway's in Vista
but I don't see them on the hylafax list hehe.
I've just heard it works with Engin so I'll test it soon. I'll have to
get new hardware unless someone creates a asterisk module that uses
spandsp for fax relay - or I'll fire up a openpbx installation.

Cheers,

Luke

On 01/05/07, Andrew Rinaldi <andrew.rinaldi@xxxxxxxxxxxx> wrote:
> Luke,
>
> >ISDN uses the same codec for voice / fax though of course we know it's
> >a completely different circuit switched medium. I have 384kb uplink
> >channel and low latency. The only thing that should cause me lots of
> >grief is packet loss in theory... theory and practise are always
> >different so we'll see.

> Regards
>
> ANDREW RINALDI
> Mainpine Limited - Support
> USA +1 503 822 9944| Asia/Europe +44 1225 869439
> andrew.rinaldi@xxxxxxxxxxxx| www.mainpine.com
>
>
>
>
>
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