[asterisk-users] Answer Supervision problem

[shadowym]

Hi Timur,

I just had to deal with a similar realization myself.  We wanted to set up
something similar to what Vonage does with simuring where Asterisk would
ring a local extension and a cell phone or landline at the same time and
route to the call to which ever answered first.  Seemed simple enough.
However, Asterisk automatically set the outgoing zap channel to "Answered"
as soon as it started ringing.  Upon further investigation I found that this
is not an exception but a rule when it comes to plain analog POT's lines.
At least in N. America.  They generally do NOT have any type of answer
supervision.  It is possible to get lines with polarity reversal for answer
supervision but that may be a special order and not available in all areas.
You would have to talk to your telco provider about this  

When your dealing with Telco's, the 2 things you DO NOT want to deal with
are any requests involving the words "special" and "not available in all
areas".  They have a hard enough time getting 100 year old POT's lines
right.  At least in my area.  You may have to speak with several different
people at the telco before you find someone who even knows what answer
supervision means.

To my knowledge, the only thing the analog cards+zaptel+Asterisk can detect
for answer supervision with Analog POT's is polarity reversal.  There is a
feature in Asterisk called "callprogress" which attempts to listen to the
line and determine answer/hangup/busy status but it is NOT reliable at all
so not recommended.

-----Original Message-----
From: Timur S. Sattarov [mailto:timur at setglobal.net] 
Sent: Thursday, November 30, 2006 10:29 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] Answer Supervision problem

Does anybody work with zaptel and analog lines ?
how to configure it in ideal case, if I really got correct answer
supervision from CO ?

regards
Tim

Timur S. Sattarov wrote:
> Hi !
>
> I've Linux Debian/testing, asterisk-1.2.13, zaptel 1.2.10 and Digium, 
> Inc. Wildcard TDM2400P with 24 FXO ports.
> Our equipment is located in US. Lines and phone numbers from AT&T.
> How can I detect answers on these lines ?
> We've discovered that during answer voltage falls and after hangup - 
> rises.
> During remote hangup there is kernel message from zaptel driver  - NO 
> BATTERY on 2/24 and then BATTERY on 2/24 (-)! and 
> hanguponponlarityswitch option in zapata.conf works fine.
> There is no such message during answer. But we can see voltage change. 
> Is there any way to detect answer like we have on hangup ?
> Or if there any possibility to detect answer through voltage changes 
> with zaptel ?
> Please help me.
>
> Thanks in advance.
>
> With best regards
> Timur.
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