| 摘要 |
PURPOSE:To prevent incoming of a malicious call by collating each pass word between a caller party and a caller so as to decide the propriety of connection to the called party. CONSTITUTION:When a caller 2 dials a pass word of a called part 1, a PB signal is detected by a receiver 7E, a scanner reads the password number, a central controller reads the result of scanning and collates it with the pass word registered by the called party. When the result of collation tells dissidence, the caller 2 is disconnected from a malicious call preventing device 7 and a busy tone is sent to the caller 2. Thus, the caller 2 cannot communicate with the called party 1 and the called party does not receive a useless incoming. On the other hand, when the pass words are coincident, the central controller connects the caller 2 and the called party 1.
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