I imagine that in theory there should be some degredation associated 
with the ATA process.  Is this noticeable?

Chris Dent wrote:
> I imagine that in theory there should be some degredation associated
> with the ATA process.  Is this noticeable?

Nope.
I expect 50% of the calls you receive come through VOIP.
Quite often on caller ID you'll see a strange number displayed like...
212309221787 (a random number) this is the IP address of the location of
 an ATA that hasn't been configured to work with called ID.

Sometimes you or the other person may haear a faint echo but on the
whole you'd never know. After all, regular telephone calls are not full
bandwidth. An international call actually takes a shorter data route
than it would if it went via Goonhilly.... I expect  :¬)

Pete

In article <Y35Ck.2275$B71.1787@newsfe30.ams2>,
Chris Dent   wrote:
>I imagine that in theory there should be some degredation associated 
>with the ATA process.  Is this noticeable?

We're talking audio with a 4.3KHz cut-off frequency before it's sampled.
Not exactly "Hi-Fi", or anywhere close.

So with that in-mind, in-theory a phone ought to be better than an ATA,
but at the end of the day, it boils down to how much you spend on the
phone. Siemens and Snom are good, Grandstream less-so (audio wise).

But good ATAs are just as good and I suspect you'd not notice.

Gordon

"www.GymRatZ.co.uk"  wrote in 
message news:gbantd$ngv$1@registered.motzarella.org...
> Chris Dent wrote:
>> I imagine that in theory there should be some degredation associated
>> with the ATA process.  Is this noticeable?
>
> Nope.
> I expect 50% of the calls you receive come through VOIP.
> Quite often on caller ID you'll see a strange number displayed like...
> 212309221787 (a random number) this is the IP address of the location of
> an ATA that hasn't been configured to work with called ID.
>
> Sometimes you or the other person may haear a faint echo but on the
> whole you'd never know. After all, regular telephone calls are not full
> bandwidth. An international call actually takes a shorter data route
> than it would if it went via Goonhilly.... I expect  :¬)
>
> Pete
My reading of the OP's question was that he wanted a comparison
between a VoIP phone and a VoIP ATA +POT given that the latter
will have an extra D-A conversion.

In theory, the all-digital (well almost) IP telephone directly connected
to your LAN (wired or wireless) should perform better. Any system
using POTs technology is putting outgoing and incoming speech
on the same pair of wires. The line interface circuit of a telephone,
the so-called "hybrid" attempts to cancel out the outgoing speech
from the earpiece, but it is considered a good thing not to over do
this so as to provide what id technically called "sidetone" or more
colloquially "blowback". As IP streams by their nature always have
a few ms delay, this can cause echo.

In practice this isn't very much of a problem and I prefer ATA+POT
for domestic use. You can get wifi IP phones of course but I
feel DECT is more robust.
-- 
Graham.

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