The following schematics design pictures is a circuit diagram FM telephone transmitter that built on a PC board layout which is so small it can simply be fitted within the housing of a telephone creating it an instant pseudo-speak earphone. This circuit diagram FM telephone transmitter components connects in series with telephone line, steals power from it, and transmit at both sides of the conversation to an FM radio tuned between 90 and 95 MHz. Detailed information you can find it here at pdf FM telephone transmitter manual book guide:
