On 2006-01-10, at 10:06, Boris Benko wrote:
Hello all!
I don't know why, but it seems that am I the only one who suffers
from echo problem? Probably not. But several implementations or *
are currently waiting, because of the echo problem.
Here is the list of measures, I tried out:
1. I have used GRANDSTREAM BUDGETONE 101 phones. They are
declaring, they have implement G.168 cancellation measures, I at
first I decided to go with them. I have tested them and it seems
they quite effectively nullify echo from most (analog) systems I
have tested. They are quite successful with analog PBXes, being
connected over several ISDN BRI connections. But I had great
troubles with ISDN DECT (cordless) phones. SIEMENS is having
several models and as far as I can tell you, echo stays in many
situations I have experienced. The problem is that here in Slovenia
is, such cordless phones were sold *EN MASS*, so still in 3 out of
10 cases, the echo problem persists. Besides, I have to use just
BT 101 phones and I am not quite flexible here. I planned to use
many SNOM phones. I'm not sure, if I am experiencing the acustic
echo with SIEMENS ISDN BRI DECT phones or not. I seems to me it is
the electrical echo, but I cannot imagine, where this echo comes
from, since there is no wire.
We had a lot of echo with Grandstream and moved totaly away from
them. All installs are now polycom phones and no echo problems.
2. I searched for some kind of boards or whatever, for me to put
them in, in order to nullify echo. No luck. Boards were either
quite expensive (and not ment for * at all), or I was quite
doubtfull, that they accually do the work. I'm pretty amazed, that
no such solution exists. I'm aware, the problem of echo must be
solved as much as close to the source channel (ISDN BRI in this
case). But this way, every driver have to have their own echo
cancelling measures supported and I think this is not the most
optimal way. But I have not found the board anyway.
Yes, something universal would be nice. Like in the unicall approach
for example ..
3. I have used the bristuff. They are stating, they are have echo
cancellation implemented. I already tried bristuff before, and I
had compilation problems. Interestingly enough, when using * v1.2.1
and bristuff 0.30.0, no compilation errors gotten. I have
implemented the usual staff - extensions, sip.conf etc etc.
The bristuff echocan is the standard echocan from zaptel
4. And yes, I have looking to use the echo cancellation in vocodec.
iLBC guys are declaring, they have counter measures implemented
(i.e. echo cancellation). Unfortunately, when implementing PBX
solutions, I usually use the G.711 mu codec, since it gives the
best (and problem less) results in local LANs. Besides, BT and SNOM
phones do not support iLBC. So, I had no luck with codec echo
cancellation techniques.
the real echocan is in GIPS NOT IN iLBC !!! And that is commercially
available from GlobalIP Sound
As far as I can tell you, bristuff cancells echo effectively. No
echo whatsoever. I have left all echo cancellation parameters
intact - as they have been declared from the beginning, not
changing the number of taps, etc. etc. 128 taps nullify echo down
to none. This works.I have not tested *international* TDM calls -
where I presume a bit more of the delay will enter the game.
I know that this is the vISDN list, but... I will stay on vISDN
list and will be ready to test the echo canceller, implemented in
vISDN. But that echo problem bothered me quite a lot and finally I
got the solution. Pheeewww....
I will be testing echo cancellation even more and will report to
this list if important matters will occur.
=b
Newer Digium hardware has hardware echo cancellation, however,
most boards still rely on the software EC in zaptel drivers. I'm
taking that canceller and putting it in vISDN.
Its performance is not exceptional but would be way better than
going without an EC :)
_______________________________________________
Visdn-hackers mailing list
[email protected]
https://mailman.uli.it/mailman/listinfo/visdn-hackers
_______________________________________________
Visdn-hackers mailing list
[email protected]
https://mailman.uli.it/mailman/listinfo/visdn-hackers
