Hello,

I am doing a project on automatic muting tv when phone rings and display the incoming call in lcd. The line voltage condition is 50.1V without ringing and 53V to 55V when receive ring signal. The frequency for the line is approximately 20Hz. Anyone can give me any relevant information or circuit diagram which i can apply in Malaysia for the above condition? Urgent!!!

 

Won't your telephone company be angry with you for tapping into a service (caller i.d.) that is normally a service for extra fee? Here in my part of the States, AT&T frowns upon people latching onto their equipment.

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The caller ID number is only provided when you pay for it, that's true. But if you don't pay, it's not transmitted, so there's no way to hack in to display it.

 

Thanks for the information.

 

About 15 or 16 years ago my teammates and I in school had to design a digital PBX and voicemail system. We used a number of Mitel and also Motorola chips for various telephony interface/features. These days Motorola doesn't seem to make chips any more. They sure make a whole lot of cell phones today... but not the chips or they don't sell it. Then the Mitel semiconductor division eventually became Zarlink of today.

Maybe go to Zarlink.com -> Products -> Telephony -> Caller ID. They may have a chip that you may be able to use here. Then wire the serial or equivalent data to a PIC microcontroller.

Try the PIC 18F family for the microcontroller. You guys can program it in Assembly or C with a free compiler. The ICSP device programmer is affordable and is easy enough to use.

Use the PIC microcontroller to send the name and phone number display data to a 16x2 or whatever equivalent text/LCD display.

The same PIC chip can hook to an infrared encoder chip to mute the TV. For this infrared encoder chip, try Holtek Semiconductor or other companies. Go to holtek.com -> Products -> Remote Controller section. Email them to ask which chip can be use to send infrared data to mute various brands of TVs.

Then look elsewhere for the sequence/codes to send a mute command. To make it "universal", send multiple codes (sequentially; one after another) for the top 5 or 10 brands of TVs and these codes probably should mute half or more of the various brands of TVs out there.

Good luck and have fun.

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I remember seeing something like this in a former electronics mag. The interface displays Caller ID data on the top left of the screen ( PIP), but doesn't mute the audio. Another interface allows fewer callers to reach you.