| 摘要 |
The apparatus includes a bridge rectifier (D6-D9) which is connected across a telephone line input. A logic circuit (62) and microprocessor (26) are used to analyse the incoming signal. Different control signals are generated as a result of this analysis, e.g. telephone receiver hooked or unhooked condition. An incoming ringing tone is detected by the microprocessor, which provides a rectified voltage feed to the telephone. The microprocessor automatically connects the telephone through a logic circuit (38) and disconnects the telephone (62) when it is no longer required. |
