Telephony
Patent 3985971 Issued on October 12, 1976. Estimated Expiration Date: 
October 12, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 12, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3584156 3626107 InventorApplicationNo. 490879 filed on 07/22/1974US Classes:379/215.01, Call Waiting379/300Having plural wiper setsExaminersPrimary: Cooper, William C.International ClassH04Q 3/00 (20060101)AbstractRelay trees connected to modified connector switches provide call-waiting service on a connector-group basis in step-by-step telephone switching systems. The subscriber's line is connected to an auxiliary line relay which functions to connect the line to the usual line circuit and bank terminals when normal, and to an auxiliary connector bank terminal when the relay is operated. Additional brushes added to the connector allow connection to the auxiliary bank terminal and to the regular bank terminal simultaneously. | |
