DTMF dial tone

[lerameur]

Hello,

When using DTMFout, does the command know how to wait for the initial dial tone to compose the number?
I have a project in mind that only need to dial a phone number, so probably a Pic16f88 directly connected to a phone line.
I have not tried it yet, but when I dial a number I pick up the phone , hear a dial tone and dial. does the DTMF command do the same ?
thanks

Ken

[mat janssen]

Do not connect the chip directly to the phoneline.
Use a small transformer (there are special tranfo's for this) .
Via an optocoupler you can detect if the phone line is open for dialing and then give the DTMF pulses for the number. Via the optocoupler you can detect is the phone at the other site is taken and then you can switch with a relay the line to the microphone and the speaker.
This sequence you can all programm into ths chip.
Succes.

[Josuetas]

No.

DTMFOUT will just generate a sound of DTMF mixed frequency.

You will have to:
HookOff (if needed)
Wait Dial Tone (about 0.6 sec)
Dial your number

[lerameur]

ok , so how do you electronically hook off then?

[mvs_sarma]

Nothing like detecting dial tone after liftthe telephone (off hook) , before starting DTMF starting. it is only time lag (few hundred mS)after Off Hook.

[lerameur]

ok but what is off hook.
I mean I have a dual splitter from the telephone line. One line goes to a telephone and the second line will go to the Pic chip. When I need to dial from the chip, how do I do an auto hook off on the telephone line so I can use the DMTFOUT command?

k