[Asterisk-Users] Echo on Zaptel FXO :(

[Phil Quinney]

Comments within:

>
>> Change fxsls to fxsks for the UK
>
> I had fxsks until today but when I was playing with the gains to try  
> and
> fix this echo issue, I found that if I dial out the Zap to one of my
> pstn->sip provider's numbers, it answered the cut off in a few seconds.
> If I dial that number on the pstn line itself without going through the
> Zap card it works fine. Someone suggested I change fxsks to fxsls and
> thas indeed did fix that problem.

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 find rxgain=2.0, txgain=2.0 to be the sweet spots for my UK setup.
>
> Is that a BT line, or NTL/Telewest?

Two cards: one BT, one NTL.
>
> So did you have echo problems when you 1st set it up?
>
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.

> How did you find that 2.0 was the best?
>
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).
>
>> The aim is to get the monitor bars in ztmonitor to be at about half  
>> way
>> when talking.
>
> I found that with calling 1471, the rx gain's showed as just below 1/2
> way with some peaks above 1/2 way on some of the words and the txgain
> was showing as 3/4 or more whatever I changed it too - even going to
> things like -8.0 (I even tried -10.0 and the call was silent so that
> must be too far!). I found this strange though, as with 0.0 the people
> i'm calling complain that i'm quiet so shurly the txgain needs to go
> up....

Talking to 1471 is one way of testing: but you really need to have  
someone on the other end to both produce sound and report on echo /  
delay.
>
>> Please also note that the X100/1P cards are not suitable for use in  
>> the
>> UK. They work on the American systems where the impedance is different
>> to the UK.
>
> Is that the true X100/1P you mean? - i.e does that include my MD3200
> chipset clone?
>
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.

> (I thought you just said you had it working well in the uk? - if so,
> what are you using and is the quality good enough not to notice that  
> you
> are using anything different than a normal phone plugged into the  
> line?)

I have it working, but its not great. As I said above I am only using  
two clone cards. What I did find though is that the quality of calls  
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.

>> You may find that asterisk reports the Zap channel as being in a
>> strange ringing state: Add busydetect=no callprogress=no to solve this
>> (I found that I could not get the devices to answer the line without
>> these set: either on my BT line or NTL line.
>
> Strange, dont seem to have had this problem - everything seems to work
> fine except for the annoying echo I hear and the other end complaining
> i'm quiet. I guess sticking them in can't harm though!
>
> --ian
>
Out of interest, what are you using for your internal phones? Sipura  
ATA?

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