john2020
Full Member level 5
dtmf switch
hi all,
i've an application wherein i have to control remote home appliances using a DTMF remote telephone switch.Once a telephone connection is in place,a transmitted tone can be used in order to trigger a desired action.This technique,well known from its use in remotely accessing answering machines or conversing with service providers,here allows us to use keypad to control three circuits once a call has been set up.The remote control switch is connected in parallel with the telephone apparatus:this doesnot restrict the use of the telephone in anyway.After a selectable number of rings the circuit lifts the receiver and sends an acknowledgement tone to signal to caller that a four-digit code number is to be entered.Ten seconds are allowed for entry of each digit,and each digit acknowledgement by a tone.if time limits is exceeded,an error sound is produced and receiver replaced on hook.Once all four digits are received they are compared with store code numbers.If digits are not in agreement with any of stored numbers,error sound is again produced and call is terminated.The circuit is then immediately ready for a new call.Each of three switching outputs is assigned two sequences of digits,one to switch output stage on and other to switch off.if same four digit number is received a second time,the circuit doesnot change state.
I am using PIC16F84,with DTMF decoder MT8870.can any one help me with this?i need C code for this project.anyone has some links pls do send me soon,i have to compelete this project soon.
regards
john
hi all,
i've an application wherein i have to control remote home appliances using a DTMF remote telephone switch.Once a telephone connection is in place,a transmitted tone can be used in order to trigger a desired action.This technique,well known from its use in remotely accessing answering machines or conversing with service providers,here allows us to use keypad to control three circuits once a call has been set up.The remote control switch is connected in parallel with the telephone apparatus:this doesnot restrict the use of the telephone in anyway.After a selectable number of rings the circuit lifts the receiver and sends an acknowledgement tone to signal to caller that a four-digit code number is to be entered.Ten seconds are allowed for entry of each digit,and each digit acknowledgement by a tone.if time limits is exceeded,an error sound is produced and receiver replaced on hook.Once all four digits are received they are compared with store code numbers.If digits are not in agreement with any of stored numbers,error sound is again produced and call is terminated.The circuit is then immediately ready for a new call.Each of three switching outputs is assigned two sequences of digits,one to switch output stage on and other to switch off.if same four digit number is received a second time,the circuit doesnot change state.
I am using PIC16F84,with DTMF decoder MT8870.can any one help me with this?i need C code for this project.anyone has some links pls do send me soon,i have to compelete this project soon.
regards
john