[SOLVED] Phone ON-HOOK Monitor to generate DTMF

[aspedon]

i'm a student, want to create circuit for monitoring phone "ON HOOK" activity, when user on hook (call end) then circuit generate dtmf "D" tone at my audio amplifier.
any there some simple circuit (without) microcontroler? please...please... ;-)
thank's

 

[tpetar]

Do you need "Line in use detector" and "On/Off Hook Detector". I'm interested why you want to generate "D" to audio amplifier ?

 

[aspedon]

tpetar:

yes. especially detect On Hook Detector. when user on hook (call end) then circuit generate dtmf "D" tone. i am monitoring dtmf ("D") via soundcard (mic) then triger my app for bill calculation. do you have an idea tpetar?

 

[tpetar]

You dont need to generate D, you can set what you want to be played or started.



Instead LED put what you want.