PURPOSE:To prevent intermission of business by a phone call from an undesired opposite party by allowing a subscriber to limit the number of sender telephone sets by which the subscriber itself is called. CONSTITUTION:When a subscriber of an extension 21 dials an extension number 3313 to call an extension 20, a controller 40 checks an incoming limit service setting storage circuit 50 and confirms that the telephone set having the extension number 3313 registers the incoming limit, the controller 40 checks whether or not the telephone number 3333 of the sender telephone set 21 is registered as a sender extension number permitted by the incoming limit setting extension number 3313 for calling by controlling an incoming limit information storage circuit 60. If it is confirmed that the number is not registered, the extension 20 cannot be reached and a restricting tone is sent to the extension 21.
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