RE: VOIP FXS Gateways that support SIP

["Ian Willoughby" <ian@xxxxxxx>]

Hi Dan,

Not being the one who made the tests, I can't say for sure but it looks
like they were talking about CSICO kit and probably the scale of there test
was larger than I would ever dream of using from home anyway. I agree it
does sound like different codec's were used. Surely SIP is also the
transport protocol as well as Signalling or am I missing something :-)

It looks like I will plump for one of the Pheenet gateways, I like the look
of the rack mount version but it works out quite expensive, the specs look
very impressive though.

R's
Ian


-----Original Message-----
From: Dan [mailto:dtoma@xxxxxxx]
Sent: Fri 02/05/2003 09:49
To: ukha_d@xxxxxxx
Cc:
Subject: Re: [ukha_d] VOIP FXS Gateways that support SIP



Hi Ian,

> Cr*p means very poor speach quality even at quite low compressions.
SIP is just a signaling protocol, so the speech quality depend ONLY on the
codec!.
So if you have the same codecs for both (H.323 and SIP) on the same device,
then the quality pf the speech is the same.
If you compare different SIP phones with H.323 phones then you can have
difference in speech quality because of the different implementations of
the
same codec.

I just make some tests on Cisco ATA-186 (both SIP and H.323) and there is
no
difference in speech quality between them for the same codec.

Do not forget the quality of the gateways used, if any....

BR,
Dan

----- Original Message -----
From: "Ian Willoughby" <ian@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Friday, May 02, 2003 11:21 AM
Subject: RE: [ukha_d] VOIP FXS Gateways that support SIP


>
> Just got this response from Solwise, I really do love Solwise honesty,
they are one of the few companies that are a real pleasure to do business
with :-
>
> I now have SIP firmware for ALL the pheenet gateways.
>
> I'm just doing a bit of testing and then I'll post it on our downloads
site.
>
> Cr*p means very poor speach quality even at quite low compressions.
Tests
carried out by one of our punters (very large VoIP carrier - like the
largest in Europe) showed that H.323 running at a 10K compressed codec out
performed SIP running at 32K compression. i.e. the H.323 produced better
results and only used one third of the bandwidth. Now maybe 32K doesn't
sound bad but remember your ADSL upstream is only 256K so get a few VoIP
calls going with SIP and you might start to get problems.
>
> Don't get me wrong here.... With MS and Cisco behind it (bl**dy 'ell
cisco
make rubbish voip kit!) SIP is obviously going to get better but I just get
the impression that, like all MS stuff, it's been launched maybe a couple
of
years too soon. Let's face it, after 18 months XP is just starting to get
useable (I'm still sticking with win2k for a bit longer). :-)
>
> R's
> Ian
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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