pulse to dtmf convertion - please help

pulse to dtmf convert

hello
I am doing my FYP. my project is switching on or off devices using telephone.
**broken link removed**
Operation:
circuit connected to telephone.
waiting for incoming call
after receiving call by pressing specific number can turn on of off devices.
i have also program the uM to detect emergency (like fire, smoke etc)
when uM detect fire or smoke an emergency number is stored will be dialed.

i have design my circuit completely, i am having little problem, when the uM dial it uses relay to make several contact to telephone line like old telephone (pulse dial or Loop Disconnect Dialing). but in my place exchange only use tone dial (DTMF).

I am lookin for a circuit which can convert my pulse tone to DTMF. so only i need to connect it to the main telephone line. when uM dial that convector circuit will convert to DTMF. Also the circuit should not interfere incoming call.
i want somthing like this
https://www.oldphoneworks.com/rotatone-pulse-to-tone-converter.html
https://www.oldphoneworks.com/pulse-to-tone-converter.html

a simple circuit that will convert pulse dial to DTMF.

pulse to dtmf convert

I think there is no need for such circuit because you have already a microcontroller in your circuit.

The microcontroller can directly generate tones for dialing. I think you will have enough space for the coding. Google 8051 dtmf generator to get help.

Another simple option is to use dtmf transceiver which can make your work simple eg. mt8880

Nandhu

Re: pulse to dtmf convert

all my uM pin are used to control other things.
only one of the pin is producing pulse which connect and disconnect the dial relay.
i am already using M8870 DTMF receiver. and it is connected to the uM.

And also I did PCB and soldered everything, so I need some extra circuit as mention above.

thank you.