[Asterisk-Users] Detecting answer supervison from an AGI app

[hwstar at rodgers.sdcoxmail.com]

Thanks John,

I'll check the manager interface out. I inderstand FXO interfaces will be useless for answer supervision.

As for gutting the payphone-- 

You should investigate updating the electronics and make it a smart payphone which is completely programmable and handles call rating locally. The original electronics in a WE SS payphone fills up most of the enclosure, but the smart board will leave you more space.

On the surface, it seems like the smart board programming is a closely held secret and only dealers have the programming software to make changes. Most of what I have learned is relevant only to the old dumb payphones which use 1700/2200Hz tones for coin denominations, continuity test between tip and grond for initial rate, and +/-130V between tip and ground to control the coin relay. 

My homebrew interface board is able to check for the presence of the initial rate in the hopper, and to collect or refund the coins in the hopper. The interface board has an RS-485 connection to the Asterisk box so that an AGI can test and control the payphone operation.  

BTW: The reason you could not simulate the tones on a payphone after the early 80's is because the phone had 
a notch filter which could be inserted in the microphone
path when the tip and ring polarity was reversed. The automated coin telephone system, and the operators reversed
the polarity on the line when coins were about to be deposited.

Steve.






> 
> From: John Todd <jtodd at loligo.com>
> Date: 2004/02/03 Tue PM 11:15:59 EST
> To: asterisk-users at lists.digium.com
> Subject: Re: [Asterisk-Users] Detecting answer supervison from an AGI app
> 
> >I've got a dumb Western Electric payphone and some homebuilt 
> >hardware to control the coin relay which is accessible to Asterisk 
> >through the AGI interface. I'd like to be able to set the state of 
> >the coin relay to collect at the end of a call if a called party 
> >answers.
> >
> >[Hey, I admit this project is being persued just for the fun of it ]
> >
> >Looking through the documentation, there is a way to get channel 
> >state, but it only tells you that the channel is
> >bridged and does not tell you the called party has answered.
> >
> >Is there another interface (unix sockets maybe?) which I can
> >use to query the answer supervison state for a given channel?
> >
> >Steve.
> 
> You can use the manager interface.  See the Wiki or various "how-to" 
> guides scattered across the four corners of Google.  You'll only be 
> able to detect answer supervision with PRI or VoIP calls outbound - 
> FXO circuits have no answer supervision.
> 
> I'm interested in your payphone application; I was given a payphone 
> for the holidays, and I'd like to semi-gut it and put an ATA type 
> device in there and an 802.11 adapter.  Feed it 110VAC and point a 
> yagi at it from a few miles away.  For that matter, ten or fifteen of 
> them.  This is one of those spare-time projects that I've been 
> intentionally ignoring, because I'll quickly become distracted with 
> trying to build a company that does wireless payphones via IP.  I 
> have the business plan mostly written in my head already.  <sigh>
> 
> I assume mine generates coin tones; it would be pretty snappy if * 
> could detect those tones and do something with them when detected 
> in-band in the audio stream.  I don't know how the payphones would 
> normally squelch these tones from being replayed into the phones; 
> that would be an interesting thing to dig around inside the phone to 
> find out about (in my free time!) because I know that playback of 
> tones became impossible in the mid 80's due to squelching locally on 
> the phones.  I like the novelty of a VoIP phone that collects coins - 
> I'm suspicious of this whole "pre-paid" thing.  ;-)
> 
> Yet Another Application That Needs Audio Processing After Dial (YAATNAPAD)...
> 
> JT
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