Telephone

Caller Line Identification displays on a (2×16) LCD the phone number of the person who is ringing you, before you even answer, this number stays on the LCD till it will be replaced by a new received phone number or if the button is pressed.
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More circuit about IC PIC16F628
More circuit about PIC [...]

Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and is therefore a good, useful [...]

This nifty little circuit lets you record your phone conversations automatically. The device connects to the phone line, your tape recorder’s microphone input, and the recorder’s remote control jack. It senses the voltage in the phone line and begins recording when the line drops to 5 volts or less. R1 1 270K 1/4 W Resistor [...]