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

[Mark Rudholm]

Jayson Smith wrote:
> Hi,
> 
>      I had a long chat with Phil tonight, and he does have some available. I
> think what I really want is just a standard payphone, not the panel type he
> has. He can get one of those for me though. It would save some shipping
> charges also!

Are you near enough to him to pick it up?  His facility is worth
seeing.

>      I have a few questions. Mark, in your design, do you envision your coin
> relay controlling device being used only for that purpose, or also hooking
> up to a source of telephone service, and having the payphone entirely hooked
> up to your device? If you don't understand, let me say it this way. Would I
> have a standard phone connection from the payphone which goes to a Sipura,
> IAXy, or other Asterisk-controlled phone service providing device, and extra
> wires going from the payphone to your proposed gizmo which would perform
> coin relay control? Or would your gizmo hook up to the device providing
> phone service, and also hook up to the payphone? The reason I'm asking is,
> I'd need to know how to tell Phil to set up the phone. He can put a modular
> plug on the phone so it can hook up to a standard phone jack, but there's
> the issue of the relay controlling wires to worry about.

Well, the coin-relay control signal is sent to the payphone's Tip and
Ground.  As long as the line coming out of the payphone has Tip, Ring,
and Ground (Ground is customarily on the yellow wire) then it's fine.

My intention is to create a small box that sits between the payphone
and an FXS port.  This small box will either connect to the Asterisk
box' USB port or parallel port (I haven't yet made up my mind).

>      Also, how are you going to handle initial depositing, in the absence of
> an initial deposit test? Will you be looking for ground on the phone after
> the user dials a number, then returning money, and asking for money, or will
> you just ask for money, or return, then ask for money? It seems to me that
> if you just ask for money without returning first, anyone who put money in
> before dialing would just have that money wasted, or have to hang up in
> order to get that money returned. As I understood what Phil told me, the
> payphone puts ground on the line when it has received a
> dipswitch-configurable amount of money, the initial deposit. This contrasts
> with what I'd earlier heard from phone phreak files talking about how you
> had to put a nickel in the phone in order to red box, because of the ground
> test.

I think there are two tests, Coin Presence, and Initial Rate Deposit.
Red boxing works with just one real nickel, so I think
ACTS is just looking for Coin Presence, not Initial Rate Deposit.
Red boxing doesn't work on local calls (that don't go through ACTS)
so local calls would seem to be keyed off of a different test, the
Initial Rate Deposit test.

I've been suffering from a bout of busyness and lack of documentation
lately, so I need to do some reading on these things, but it's really
not important, since if you set the Initial Rate (those DIP switch
settings Phil mentioned) to 5 cents, the Initial Rate and Coin
Presence tests stop mattering.  All you have to do at that point is
listen for the coin tones, since setting the Initial Rate to 5
cents causes the phone to send coin tone for *any* coin deposit
(since it's impossible to deposit less than 5 cents)

So at that point, the ground-related Coin Presence and Initial
Rate Deposit tests become unnecessary for our purposes.

>      Sorry for such a long message, but I'd love to get these questions
> answered.

I hope I did that.  ...if not, you can try reaching me on CNET
377-0500.  I'm on Pacific Time and usually up until about 1:00 AM

-Mark