| 摘要 |
PROBLEM TO BE SOLVED: To provide a terminal adaptor that restricts communication or releases the restriction only with hook information. SOLUTION: A hook information analysis circuit 13 receiving hook information in succession to an off-hook signal from an analog telephone 30 refers to a communication restriction state table and the analog telephone 30 discriminates a communication restriction release state or a communication restriction state. When the analog telephone 30 is in the communication restriction release state, the hook information analysis circuit 13 stops transmission of a dial tone to the analog telephone 30 to instruct communication restriction to an analog telephone interface control circuit 15 so as to restrict call transmission from the analog telephone 30 and call reception by the analog telephone 30. On the other hand, when the analog telephone 30 is in a communication restriction state, a dial tone is sent to the analog telephone 30, an instruction to release the communication restriction with respect to the analog telephone 30 is sent to the analog telephone interface control circuit 15 to bring the analog telephone 30 into the communication restriction release state and into a communication available state.
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