[Asterisk-Users] Current echo status?

[Joshua McClintock]

We're using asterisk in production at my place.  We have about 45 users
(33 snom 200 sip phones and the rest on soft phones).  We're connected
to the telco via a pri (23 useable channels) using the digium t1 card. 
We have another t1 card hooked to an adit 600 channel bank for analog
services.

Internally, sip2sip calls, you can't hear any echo.  Anything that heads
out over the pri is really pretty good.  Unless you have cyborg ears,
you don't hear much, if any echo (at least the users haven't
complained).

One thing that bites on the snom 200 is the speaker.  It seems to be
very choppy sounding.  Someone here seems to think the VOX chip is junk,
but I really don't know what the deal is.

We've plugged in our normal (analog) conference phone via the channel
bank and it kicks butt.  The adit 600 is a good device.  We can
send/receive faxes (the standalone modems seem to be ok as well, though
I haven't seen at what rate their connecting at, we only use 'em for
payroll and the postage machine so pry 9600).

The PoE seems to work flawlessly (we're using the powerdsine 24 port
midspans).  

Out of 33 snom phones, 1 couldn't use PoE (external ps works), 1 worked,
but the internal ps seemed to give out, now it won't power on at all, 1
spontanously reboots, and 1 seems to have a problem with it's on hook
button.

Watchout who you buy them from, as the company we ordered from is a
disgrace, getting these rma'ed is a total pain (still not done).  I
would almost suggest setting yourself up as a reseller and buy directly
from the closest distributer (I don't know if they charge a fee or not).

On Thu, 2004-07-15 at 16:13, Scott Laird wrote:
> I've been following the list for months, and I have a working Asterisk 
> setup, but it'd be *really* useful to me at this point if someone could 
> summarize when Asterisk has echo problems and when it doesn't.  For 
> instance, I usually hear a far-end echo when talking on my 7940, but 
> not when using a POTS phone plugged into a TDM400 FXO port.  It doesn't 
> seem to matter if the call goes out over a POTS line or via NuFone; 
> either way there's a fair bit of echo on most (but not all) calls.
> 
> Do different SIP phones have better echo cancellation then the Cisco 
> 7940/60s?  How about the Polycom IP500/600s?
> 
> Does it matter if calls go out via POTS/T-1/PRI/VoIP?
> 
> The general impression that I've received is that "fast" channels 
> (basically traditionally telephony interfaces) don't exhibit noticeable 
> echo, but the slight delay associated with VoIP packetization unmasks 
> existing echo.  Is that a reasonable summary?
> 
> We're starting to plan for a new office build-out at work, and I'd love 
> to use Asterisk and SIP phones in the new office, but I'm not going to 
> try to sell management on a phone system with a horrible echo problem, 
> even if it will get fixed eventually.
> 
> Thanks.
> 
> 
> Scott
> 
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