Hai sir,
I am doing a project on cellphone based remote controller for water pump.i have just connected the dtmf decoder part using ic mt8870 and connected leds to pin 11,12,13,14 . When I supplied a 5 v as vcc ,1 leds lights up without cellphone in the circuit.i have not connected the cell phone to the circuit but one of the leds light up what can be the reason. Also can we connect all cellphones,to the circuit. How can I connect my cellphone with the circuit. Pls rply soon.if possible today itself.

 

can you post your circuit please?


manual

 

How are you connecting your cell phone to the pump? Does it have its own number? The decoder is meant to read signals from a land line.