RE: Echo on the phone line

["Chris McGookin" <chris@xxxxxxx>]

Hi Paul,

I doubt this is your cabling although I could be wrong. More likely to
be a faulty phone or a dodgy piece of telco equipment. I assume that
your extensions to node 0 have been made using BT CW1308 telephone cable
or cat5e and that you've checked the connections?

First, does it happen with all phones?- try a process of elimination to
see if you have a faulty instrument.

Second, does it happen more on particular calls, i.e. to/ from mobile or
using a low cost routing?
Things such as going from PCM to ATM or PCM to IP in the transmission
network can creating delays and consequentially introduce echo...

For instance, some legs of a call along a transmission route may convert
the PCM digital call from the exchange/ basestation, etc to packet for
instance, where this is done echo cancellation is applied and often
actually adjustable for the individual channel...

In the relatively frequent occurances of echo we've had on our internal
network we've found that transmission hardware defects are the most
common cause end to end. We have occassionally tweaked the echo
cancellation settings in switches but this is a bit of black magic
really with very few wizards in even the big telcos. They'll usually
never even be looked at from new and probably never before the first 10
(100?) support call to your telco... ;-)

If you think it's the latter then the more you can narrow down the
source/ destinations the better...

Chris


-----Original Message-----
From: Paul [mailto:p-gale@xxxxxxx]
Sent: 28 April 2003 10:14
To: ukha_d@xxxxxxx
Subject: [ukha_d] Echo on the phone line



A question for all you telephone experts...



Some time ago, I re-located both my analogue BT master socket and Home
Highway master sockets to node 0. I ran the cables via Cat5e and
straight to the new location of the master sockets. I then distribute
the lines through a patch panel (each line wired to 3 patch ways but
only one used on each).



On the analogue line I've noticed a bit of echo now and then - Some
callers say that they get really bad echo sometimes (their end is much
more noticeable than this end though).



Any thoughts as to what may be causing this?



Ta.



Paul.





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