Dialer detecting end user hookup

[lerameur]

Hi,
I am not sure on how to do a handshake. I am not in control of the receiving end. there are only two options, either the person picks up the phone or not.
It is not like me programing a RS232 where I am in control of both ends. I am not sure I understand the handshaking thing.
This is the code I use for dialing, I would just like to add the receiving off hook, programing bit so I have more control over the dialing process.
(If that works then I will probably use the ISD4005 voice chip.. but I am not there yet.)

Dial1760: 'cel
lcdout $FE,1, "dialing1760 ",dec counter
Pause 500
PortA.1 = 1 'Activate relay
pause 3000
DTMFOUT PortA.0, 500, 100, [5,5,4,4,9,5,4,3,6,2] 'dialing
'Set the OnTime to 500ms and OffTime to 100ms - for sure receiving
pause 8000 'Pause 8 seconds 'wait for enduser to pick up
DTMFOUT PortA.0, 6000,0, [5] 'signal
pause 2000 'Pause 2 seconds
PortA.1 = 0 'deActivate relay
pause 5000 'Pause 5 seconds
return

K

[Bruce]

Have a look at some of these examples. You might find something useful.
http://www.melabs.com/resources/samples.htm#xtpbp

[lerameur]

Bruce,

interesting program, but I am still a bit confused. Seems to me that this program act like both the dialer and receiving end.
This line in the program: IF (j > 60) OR (key = 12) Then stop_ringing
seems to only stop ringing if the person dialing decide to stop the ringing or the counter finishes its loop.
What about if the person at the other picks up the telephone, how would it know to stop ringing?
thanks

Ken

[Bruce]

I have not looked at or used any of these code examples, but they do show how to detect
off-hook conditions and a lot more. Just figured you could find something useful in there
somewhere.

[ardhuru]

In the old days, the voltage polarity on the line used to flip when the called party lifted the phone; very easy to detect using an opto. Havent tested if this is still the case for a long time.

Regards,

Anand