asterisk users - Jun 2006 - EC needed in all-digital situation?

I was just told that for my forthcoming system I will be getting a data
T-1 instead of a voice T-1.  Given that all of the handsets will be voip
phones, no analog at all, do I need echo cancellation?  I looked at the
voip-info wiki and it seems to me that the answer should be "no" but I
would like to confirm that.

TIA,
W

Warren wrote:
> I was just told that for my forthcoming system I will be getting a data
> T-1 instead of a voice T-1.  Given that all of the handsets will be voip
> phones, no analog at all, do I need echo cancellation?  I looked at the
> voip-info wiki and it seems to me that the answer should be "no"
but I
> would like to confirm that.
If you never make calls to analog phones or receive calls from analog 
phones, then you will never have echo.

Can you be sure that all telephones you call out there on the world PSTN 
will always be digital?  I didn't think so.

-- 
Now accepting new clients in Birmingham, Atlanta, Huntsville, 
Chattanooga, and Montgomery.

On Thursday 15 June 2006 10:22, Warren wrote:
> I was just told that for my forthcoming system I will be getting a data
> T-1 instead of a voice T-1.  Given that all of the handsets will be voip
> phones, no analog at all, do I need echo cancellation?  I looked at the
> voip-info wiki and it seems to me that the answer should be "no"
but I
> would like to confirm that.
All-digital setups do not *generate* echo since there is no hybrid circuit to 
reflect energy.  However all-digital systems can still have echo if the 
far-side is a 2-wire system and the latency is sufficiently high.  (Anything 
with a PCI bus can bring this latency up easily.)

Also, if you have an ueber-cheap phone which acoustically couples the speaker 
in the handset with the mic you can introduce echo on your all-digital system 
that way.  The same goes for cheap speakerphones and/or acoustically
"hard"
rooms.

-A.

>If you have no TDM equipment, then it is your provider's responsibility 
>to handle any echo that may be generated if a call is routed through the 
>PSTN.
Case in point: I have 2 installs, both exactly identical. Same Asterisk rev,
same phones, same Digium cards, everything. In 1 install we have a dual PRI
from Allstream/MTS, in the other, BRI's from Telus. On the Allstream
install, we have the classic hybrid echo when calling to a local exchange,
and on the BRI install, nothing, no matter where we call. Ironically, the
dry pair to the CO on the Allstream install is provided by Telus.

try PINS, they are in NY, but cover the area. I have SIP from them in Lake
Ronkonkoma and Woodmere
www.pins.net

Speak to Mike Lavelle


On 6/16/06, Warren <warren-lists@icruise.com>
wrote:
>
> Does anyone have any experience with providers on Long Island?  We are
> in Lynbrook, but I believe all of the Long Island providers cover the
> entire area.
>
> TIA,
> W
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-- 
Richard C. Schroeder
rschroe@gmail.com
rschroe@optonline.net
5268591129@tmomail.net (SMS)
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