| 摘要 |
PROBLEM TO BE SOLVED: To provide the interruption preventing device of a telephone which completely inhibits the introduction of AC induction noise and which operates only by power supply from telephone line terminals. SOLUTION: When a telephone set TEL2 becomes a call state, the light- emitting elements PM1-L and PM2-L of a photo MOS relay emit light and the switch elements PM1-S and PM2-S of the photo MOS relay, which are connected to a telephone set TEL1, becomes off state. Thus, connection ends of the telephone set TEL1 are separated from telephone line terminals L1 and L2. The dark resistance of the switch elements becoming an off state is considerably high. Thus, the introduction of AC induction noise to the telephone set TEL2 from the telephone set TEL1 can completely be inhibited.
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