[Asterisk-Users] Re: Can anyone explain reason for this echo

[Eric Bishop]

On 11/18/05, Andrew Kohlsmith <akohlsmith-asterisk at benshaw.com> wrote:
>
> On Friday 18 November 2005 00:30, Eric Bishop wrote:
> > I purchased the following item:
> >
> http://www.oriontelecom.com/echo_canceller/1u_telnet/e1_1u_19inch_ec.html
> >
> > As you can see not a very highly spec'd product but does the job well.
>
> Perhaps not highly specc'd but with tail lengths of 64ms bidirectional or
> 128ms unidirectional, it's already more capable than the software
> cancellers
> (16ms unidirectional with echocancel=128) and I believe that the VPM isn't
> all that much better, but I'm not 100% sure now that I can't find the
> specs
> on it.
>
> > I don't accept the fact that mine is a special case. In fact if anything
> it
> > should be better than most other scenarios as we are using Tier 1
> hardware
> > (all HP), Digium Rev 2 firmware and our rack is about 10 metres from the
> > CO.
>
> None of that really matters -- it's the overall disance from your RJ48 to
> the
> far end's phone that determines the TDM delay, and delays in your
> motherboard's PCI implementation that cause echo. By far mostly the
> latter.


Andrew, I really don't buy that. Everyone seems to blame everything else
other Digium for faulty products. Would you be as soft on the vendor if it
was Microsoft?

The simple fact is they have made a fantastic PBX software product and along
with some reasonably priced PC telephony hardware. However echo elimination
is clearly lacking in all their products. If you simply take this fact into
account when planning installations, you will save yourself a lot time and
trouble.


-A.
> _______________________________________________
> --Bandwidth and Colocation sponsored by Easynews.com <http://Easynews.com>--
>
> Asterisk-Users mailing list
> Asterisk-Users at lists.digium.com
> http://lists.digium.com/mailman/listinfo/asterisk-users
> To UNSUBSCRIBE or update options visit:
> http://lists.digium.com/mailman/listinfo/asterisk-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20051118/8912d9ed/attachment.htm