[VoIP] Asterisk and Payphones

Steph Kerman stfkerman at jps.net
Sun Aug 5 11:40:43 CDT 2007 

The adapter could send a 4th column DTMF digit or special digit sequence 
using * and/or #.  Or it could send a special timed wink or dial pulse 
digit.  Lots of possibilities.  Since * knows that this is the 
disconnect at end of the call, even dial pulse digits could be used as 
control signals without possible misinterpretation.

Steph

Jayson Smith wrote:
> Hi,
> That's true. But, without Asterisk knowing the coin phone has been hung up,
> how would it know to send the coin disposal tone? Seems to me, my little box
> would sit around waiting forever, for a coin disposal tone which would never
> come, since Asterisk thinks the phone is still off the hook.
> Jayson
>
> ----- Original Message ----- 
> From: "Steph Kerman" <stfkerman at jps.net>
> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
> Sent: Sunday, August 05, 2007 11:38 AM
> Subject: Re: [VoIP] Asterisk and Payphones
>
>
>   
>> Jayson,
>>
>> The problem of the phone's hanging up preventing coin disposal is easily
>> solved.  The coin control adapter you envision can have control over
>> supervision towards the FXS or ATA.  If so, even if the telephone goes
>> on hook the coin control adapter can keep the FXS or ATA off hook until
>> it receives the coin disposal tone and executes it.
>>
>> Steph
>>
>> Jayson Smith wrote:
>>     
>>> Hi,
>>> Actually, I'd originally come up with a different approach for handling
>>>       
> coin
>   
>>> collect and return. The approach I'd thought of, as well as others, I
>>>       
> think,
>   
>>> was using the bluebox/greenbox tones to signal a box which sat between
>>> Asterisk and a coin phone. The problem with this approach is that if the
>>> coin phone hangs up, Asterisk is never going to get to send the
>>>       
> appropriate
>   
>>> tone down the line, so the coin(s) will just sit there in the holding
>>> chamber or whatever the technical term is, until another call is made.
>>>      Would this circuit work with an ATA, or just with an FXS card from
>>>       
> the
>   
>>> Asterisk box, or either way? The way I'm seeing this, the computer has a
>>> connection into a box. The box has two phone connections. One goes to a
>>> source of phone service, be it an FXS port, an ATA, or whatever. The
>>>       
> other
>   
>>> goes into a coin phone.
>>>      Assuming this project gets completed, or at least in a workable
>>>       
> state,
>   
>>> I might have to think about seriously looking for coin phones. I've
>>>       
> always
>   
>>> been afraid, if I actually bought one on eBay, that the seller would ask
>>>       
> all
>   
>>> sorts of questions like, "What do you want this for? You want to have a
>>> payphone in your home? Don't you know that under federal law number
>>> 1234-56789-x3-qrj49, paragraph 29, subparagraph 4C, subsection 21J, it
>>>       
> is
>   
>>> illegal to have a working payphone in your home, with the minimum
>>>       
> penalty
>   
>>> being fifty years sitting in one room and listening to the same
>>>       
> telephone
>   
>>> recording again and again and again?" Ok that got a bit crazy, but until
>>> now, the only type of payphone which would have even been useful to me
>>>       
> as a
>   
>>> working payphone would be a COCOT. I assume those phones you see on
>>>       
> eBay,
>   
>>> converted for home use, no coins needed, any coins deposited go straight
>>> into the coin box, have had all their coin guts ripped out so as not to
>>>       
> be
>   
>>> convertible into a working payphone again?
>>>      On another subject, does anybody have a full set of ACTS
>>>       
> recordings, or
>   
>>> were you figuring on having Allison record some things, or what?
>>> Jayson
>>>
>>> ----- Original Message ----- 
>>> From: "Lee Spenadel" <lee at spenadel.com>
>>> To: "'Voice Over IP Tandem for Analog Switches'" <voip at ckts.info>
>>> Sent: Tuesday, July 31, 2007 8:29 AM
>>> Subject: Re: [VoIP] Asterisk and Payphones
>>>
>>>
>>>
>>>       
>>>> Mark,
>>>>
>>>> My BSP for the 1D/2D Coin Telephone Set shows:
>>>>
>>>> Operate Current: 41 mA
>>>> Non-Operate Current 30 mA
>>>> Operate Time of 450  +/- 50 ms
>>>>
>>>> Lee
>>>>
>>>> -----Original Message-----
>>>> From: voip-bounces at ckts.info [mailto:voip-bounces at ckts.info] On Behalf
>>>>         
> Of
>   
>>>> Mark Rudholm
>>>> Sent: Tuesday, July 31, 2007 1:16 AM
>>>> To: Voice Over IP Tandem for Analog Switches
>>>> Subject: Re: [VoIP] Asterisk and Payphones
>>>>
>>>> Well, I'm glad to hear there is significant interest in this.
>>>>
>>>> For the moment, I'm working on coin-relay control.  My first
>>>> draft of the schematic is available here:
>>>> http://rudholm.com/coin-control.pdf (use "File, Rotate" to
>>>> fix the orientation in Acrobat Reader).
>>>>
>>>> My idea is just to take two TTL lines from the computer, either
>>>> from the parallel port or from a USB to parallel adapter
>>>> (like the Elexol USBMOD4), one for return vs. collect and
>>>> the other as a strobe to trigger the relay.  If I use the
>>>> parallel port, I'll need to add a +5VDC power supply to my
>>>> interface box to power a TTL buffer since parallel ports
>>>> can't source or sink enough current to safely drive those
>>>> solid-state relays.  The Elexol interfaces can source enough
>>>> current to operate them however, and also since USB ports
>>>> have a nice 500mA +5VDC supply line, I could throw in a
>>>> buffer as well.
>>>>
>>>> I'll build the circuit described in that schematic on a
>>>> proto board as soon as my Mouser order for the parts arrives.
>>>> Once I get it working right and get the relay timing right,
>>>> then I'll start thinking about the TTL control lines.
>>>>
>>>> Speaking of which, if someone could look up in their Coin
>>>> Crafts or Coin Services Manual Volume I what the coin relay
>>>> timing is, I need that information.  I'm guessing it's
>>>> about 500ms but would like verification.
>>>>
>>>> Once the hardware is done, it shouldn't be too hard to
>>>> do a simple return or collect from Asterisk based on whether
>>>> the call supervised or not.
>>>>
>>>> Mark Spencer pointed out to me that DTMF detection is
>>>> actually not done in zaptel but in a simple goertzel analysis
>>>> in dsp.c, which makes sense for DTMF decoding.  He suggested
>>>> I just add a new column and row for 1700 and 2200Hz coin
>>>> tone.  I figure I'll start hacking the code once I get the
>>>> hardware working.  I would ultimately like to be able to
>>>> fully emulate ACTS.
>>>>
>>>> I would eventually like to add the Stuck Coin, Coin
>>>> Presence, and initial rate deposit tests to the system.
>>>>
>>>> Support for coin first phones would be nice, but I need
>>>> to get my hands on the Coin Services Manual to even start
>>>> thinking about how I'd support all these functions.
>>>>
>>>> Three-slot support would be interesting.  I understand the
>>>> coin bells are tuned so it shouldn't be too hard to
>>>> add the two tones to the goertzel analysis (one for the
>>>> nickel/dime bell, and one for the quarter gong).
>>>>
>>>> My ultimate goal would be to publish a patch set for the
>>>> relevant files in asterisk and a schematic and Mouser
>>>> part number list.  The circuit is too simple to really
>>>> justify custom printed circuit board artwork (it someone
>>>> wanted to do that, that'd be fine with me, though).
>>>>
>>>> -Mark
>>>>
>>>> Greg Blakely wrote:
>>>>
>>>>         
>>>>> I don't know if you'd be able to include a 3-slot patch in the
>>>>>           
> project,
>   
>>>> but
>>>>
>>>>         
>>>>> my payphone is a pre-pay 3-slot Automatic Electric.  It has the "ding"
>>>>>
>>>>>           
>>>> bell
>>>>
>>>>         
>>>>> for nickels and dimes, but using a "gong" for a quarter.
>>>>>
>>>>>           
>>>> _______________________________________________
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>>>>
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>>>>
>>>>
>>>>         
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>>>       
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