[Asterisk-Users] Echo on Zaptel FXO :(

[Phil Quinney]

Comments within:

>
>> If you stick with fxsks and add busydetect=no and callprogress=no
>> you'll find those random disconnects go away. They did for me.
>
> I just tried that and I still got the disconnection so I changed it  
> back
> to fxsls but left those 2 lines in zapata.conf for good measure!
>
>
>> Yes. The echo drove me and my parents mad. It was the same issues as
>> you are describing. Echo at near and far end and the caller on the
>> other end says you're quiet.
>
> Ah, that's good news that you had the same problem and fixed it. I just
> tried 2.0 and 2.0 and still got the echo though :(
>
The thing is I didn't completely fix it. Our calls usually use our main  
BT line, but I use the NTL line for calling in. The echo is  
substantially lower (pretty much unhearable) on the NTL line compared  
to the BT Line, so you have a fairly good chance (hopefully) of getting  
a decent solution.

> Which NTL exchange are you on, out of interest. I'm in Teesside on the
> stockton ubr.
>
I'd like a little anonymity but I'm in the Midlands.
>
>> Through a number of mobile phone calls using T-Mobile free minutes to  
>> a
>> phone in another room (with my little brother as a testing  
>> guinea-pig).
>
> So you just kept randomly chaning them until it sounded the best?
>
Basically. It was something to distract from exams.

>> I'm using two X100P clone cards (actually 101P's). Supposedly these
>> clone cards are exactly the same as a Digium X100P but I haven't ever
>> compared them.
>
> So is that a modem with the MD3200 chipset? (which is what i'm using)  
> or
> is there other clones around?
>
I'm not exactly sure on the clone specifics. Mine are identified in  
lspci as:

00:0a.0 Communication controller: Tiger Jet Network Inc. Tiger3XX  
Modem/ISDN interface
00:0c.0 Communication controller: Tiger Jet Network Inc. Tiger3XX  
Modem/ISDN interface

>> was significantly better if the cable used to connect the X100P to the
>> telephone point consists of a BTPlug to RJ11Socket adaptor and a cable
>> with two RJ11 connectors on each end. Make sure that only the two
>> central pins are used on the RJ11 connectors. On one of my cards at
>> least this drastically reduced echo.
>
> humm, interesting. So your rj11->rj11 cable only has 2 pins, the center
> ones?

Yes. I'm not an expert in why but it really reduced the echo! It could  
have been an initially fault cable though.

>
>> Out of interest, what are you using for your internal phones? Sipura
>> ATA?
>
> Yes - an SPA-3000 with a BT Converse and some DECT cordless attached.
> The SPA-3000 is good because if the power/network dies, the phones  
> still
> work because it bridges them to the pstn line.

OK. Here is something completely different for you to try:

In the web interface of your Sipura go to Regional and change the FXS  
Port Impedeance to 370+620||310nF. This is the correct impedance  
setting for the UK and improved echo problems I had which only affected  
the BT Studio 100 dect phones we have.

> How did you know/guess I was using a Sipura?
>
I'd like to say I knew, but it was just a guess. To be honest I was  
just hoping because I have an SPA-2000 and knew about the above  
setting!

Why don't you use the PSTN line on the SPA-3000 instead of the X100P?  
People are reporting much better results with the SPA-3000's PSTN port  
than with an X100P (in the UK).

Phil.

------------------------------------------------------------------------ 
--------------------------
Phil Quinney
IT Consultant - Any-Ideas