MULTI-TAP DISTRIBUTION BOX FOR COMMUNITY ANTENNA TELEVISION SYSTEM

摘要

A multi-tap distribution box for a community antenna television system. The box is interposed in a primary cable carrying video and radio signals from a master station to subscribers who are linked to the cable by drop lines coupled to the taps. To prevent illegal taps, security keys are provided, each of which is insertable in a keyway associated with a tap. When fully inserted, each key is received by a connector whose circuit, in the absence of a key, is adapted to terminate the related tap and thereby prevent the transfer of signals to the subscriber, the connector circuit, in the presence of a key, rendering the tap operative. A guard system is provided which in one phase blocks all keyways to prevent the entry of keys therein, in another phase unblocks the keyways to permit insertion of keys in selected keyways, and in a third phase captures the inserted keys to prevent removal thereof, and also blocks the remaining keyways to preclude the entry of additional keys. Also provided are means to lock the guard system in the third state to maintain status quo, whereby the only taps which are operative are those which are legal.