[Asterisk-Users] Any echo issues with phones from TDM400P > X100P

[Rich Adamson]

> Hi,
> I'm thinking of purchasing a TDM400P card and was wondering if anyone has 
> experienced any echo issues with phones off these cards connecting to the 
> PSTN via the X100P cards?
>  
> I have had my fingers burnt with a Voip phone > X100P.

I replaced two x100p's with a tdm04b 4-port fxo card, and the echo problem
with pstn lines are absolutely no different; echo is still there and I've
spent a substantial amount of time attempting to improve it (as an ex-
telco engineer). Three pstn lines from two central offices all identical.
Attaching these same three pstn lines to a Mediatrix 1204 totally 
eliminated all echo, however the 1204 had other problems that caused 
me to return it to the reseller. Tried ever combination of echo cancellation
options in Make and *.h files that folks have suggested, problem is
still there and most disturbing during the first 15 seconds of all calls.

As a non-programmer and * user for over nine months, its my opinion (right,
or wrong) that past echo problems have had two sources; one from pstn 
mismatch problems that have been heavily discussed since about September 
2003. The other source has not yet been found/diagnosed and "seems" to 
be system dependent (and its not irq related either). You either have
it or you don't, and the few developers that have either the x100p or
the tdm card installed, don't seem to have the problem. Therefore diagnosing
the root cause is still waiting on someone with the problem _and_ the
programming skills.