[Tutor] Telephone app

[bob gailer]

On 1/23/2011 4:04 PM, David Hutto wrote:

Warning - do NOT connect a telco landline to a USB port. The line 
voltage when "on hook" is around 50 V and rises over 100 when ringing. 
That will certainly fry the port.

There are expansion cards and other devices designed to connect to the 
landline and to a phone. They also process caller id and send touch tone 
signals.

I've tried to follow your explanation. It is too vague for me to make 
sense of.

I guess you want to take the line that comes to you from your local 
telco, stick something computer-wise between it and an ordinary analog 
phone, so the computer can receive and process the caller id from an 
incoming call, and also ensure that the caller id appears on the phone 
itself, and use the computer to dial numbers (NOT known as caller id).

Correct so far?

> It's two fold. First is the obvious of conducting a call/receiving the
> caller id info.

May be obvious to you, but not to me! To support your query please 
provide some kind of wiring diagram and define "conducting a call".
> The second is to send directly to the phone, and transmit the caller id data.

Again this is not very precise or clear. What do you want to send to the 
pone?
> By flow through, I mean that the phone has one of 2 states(on the
> hook, off the hook)
I'm OK with that.
> off the hook in use/off the hook not in use).

That is not clear.
> On the actual phone we pick up the receiver, or press the button on
> the cordless to receive, but the line is always connected, meaning it
> stops at the phone(terminal). I pick up the receiver, and transmit a
> series of specific tones which indicate the area code, trunk number
> and extension(if I remember this correctly, it's been a while since I
> studied the phone itself).
>
> So I have to receive the signal that the phone is ringing(then I'm
> assuming it sends the caller id info in between rings in some form)/or
> transmit a series of tones to them to connect.

Huh?
> So I think my main question is what modules might be relevant to doing
> this?

As someone mentioned earlier - TAPI is your friend.
> And should I be thinking of it any differently than a USB port
> which has 4 pins two data(+-), and two dc current(+-)?

As I warned above, YES.


-- 
Bob Gailer
919-636-4239
Chapel Hill NC