| 摘要 |
PROBLEM TO BE SOLVED: To provide a telephone line/doorphone switching adaptor whose configuration can easily be revised to avoid malfunction in the case that a telephone line is changed into a digital channel. SOLUTION: The telephone line/doorphone switching adaptor is provided with a setting switch 19 that sets validity/invalidity of a changeover section 11, which selectively connects a communication unit to a telephone line L or a doorphone 3. When the doorphone 3 makes a call in a state that this setting switch 19 is set to a position of the validity, the changeover section 11 changes the connection of the communication unit from the telephone line L to the doorphone 3. On the other hand, when the doorphone 3 makes a call in a state that this setting switch 19 is set to a position of the invalidity, the changeover section 11 maintains the connection of the communication unit to telephone line L.
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