[VoIP] Questions about payphones (was Re: CAMA and UK billing)

[Jayson Smith]

Hi,

     I came across this tidbit while reading the document Donald attached a
bit earlier:

Reversal of tip/ring polarity is needed at the coin terminal for two
reasons. The first is to
reset the totalizer to a toll mode whereby single-coin deposits will enable
coin tone
generation The second reason is to enable an option whereby a
polarity-sensitive filter
could be inserted in the voice path of a coin terminal to defeat fraudulent
simulation of coin
tones with acoustically coupled devices. Reversal of tip/ring polarity can
occur as a result
of in-band signals from an OSS or can be initiated by the local switch
itself. See TR-NWT-
000506, Section 6.2.9.5, for more information.

What this sounds like is that, when ACTS comes on the line, it reverses the
polarity in order to tell the phone to start sending coin tones, even if no
initial deposit has been made, and also to optionally enable a filter to the
mouthpiece in order to prevent red boxing. Hope this helps.
Jayson

----- Original Message ----- 
From: "Mark Rudholm" <mark at rudholm.com>
To: "Voice Over IP Tandem for Analog Switches" <voip at lists.ckts.info>
Sent: Sunday, August 19, 2007 3:18 AM
Subject: Re: [VoIP] Questions about payphones (was Re: CAMA and UK billing)


> Jayson Smith wrote:
> > Hi again,
> >
> >      If I understand correctly, the last coin necessary to meet or
exceed
> > initial deposit is signaled via tones. So if it's set to 5c, and you
drop in
> > a nickel, that will be signaled. But if it's set to 20c, and you drop in
> > four nickels, the first three aren't signaled, but the fourth one is. Is
>
> No, that's not quite right.  The first three don't generate coin-tone,
> but when you drop in the fourth, the totalizer then sends out the tones
> for two dimes.  So it queues up the coin deposits until you satisfy the
> Initial Rate deposit and then sends them all at once.
>
> > that right? Have you monitored the electrical properties of the line
when
> > ACTS comes on the line to try to find out what ACTS is doing to signal
the
> > phone to start sending coin tones, even if initial deposit hasn't been
made?
>
> No, I have not done this extensively.  I was trying to get a hold of
> a copy of the Coin Service Manual Volume I that describes all of this
> but missed a couple of opportunities to buy one on ebay.  I now have
> a scanned copy of this book, but it's a bit painful to read since the
> pages are randomly inverted.
>
> If anyone has a copy of this book they'd like to sell, it really
> would be of much help to me for this project...
> _______________________________________________
> VoIP mailing list
> VoIP at lists.ckts.info
> http://lists.ckts.info/mailman/listinfo/voip
> Project Web Page: http://www.ckts.info/
>