发明名称 METHODS AND APPARATUS FOR CONTROLLING ACCESS TO TOLL FREE TELEPHONE SERVICE
摘要 <p>A system (10) for controlling access to communications lines (30) is disclosed. The system includes a personal device (12) and a central device (16). The personal device (12) includes a communications link address circuit embodying a plurality of addresses (44), an algorithm circuit (42), a processor (50) and a transmitting module (22). The processor (50) selects an address in accordance with the algorithm which is transmitted by the module (22). The central device (16) has a selection circuit (60) which designates one of the communication lines (30), retrieved from a candidate circuit (62), as an accessible link in accordance with the algorithm.</p>
申请公布号 WO1993021720(A1) 申请公布日期 1993.10.28
申请号 US1993003572 申请日期 1993.04.15
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