| 摘要 |
PROBLEM TO BE SOLVED: To attain communication with a central monitor center even in the case of a model of an automatic notice unit automatically transmitting data to the central monitor center cannot immediately restore a line voltage when an analog port of a terminal adaptor used for connection to an ISDN line is hooked on from an off-hook state. SOLUTION: The automatic notice unit is provided with a control section 4 having a function that acquires a telephone line 9 at a high impedance by detecting off-hook when a customer terminal 16 hooks off a ringing call from a central monitor center 11 for its reply and acquires the telephone line 9 at a low impedance when a password received from the central monitor center 11 is coincident.
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