| 摘要 |
<p>This circuit utilizes the customer's own tip and ring lines to allow the customer selectively to transfer incoming calls from a primary equipment location (e.g. a primary telephone) to an auxiliary equipment location (e.g. answering bureau). A manually operable, double throw switch on the customer's premises is connected to the loop of the customer's primary phone, and in one position connects the primary loop directly to the associated telephone company's COE (central office equipment). In its other position the switch allows current leakage in at least part of the primary loop, and a sensing network effects energization of a transfer relay if the leakage current is sufficient and flows in the proper direction. The energized relay transfers the COE to the customer's auxiliary equipment location. Slave circuits controlled by the transfer relay may effect transfer on a multitude of central office lines. The transfer on each loop is only activated when that loop is idle.</p> |
