Telephone privacy protector
Patent 4747128 Issued on May 24, 1988. Estimated Expiration Date: 
May 22, 2006. 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.
May 22, 2006. 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 2001095 3499121 3504128 3514544 Telephone privacy device Line security device Line status apparatus for telephones Telephone privacy controller Patent #: 4332983 InventorsApplicationNo. 06/865682 filed on 05/22/1986US Classes:379/194, Lockout or double use signalling379/387.01SUBSTATION OR TERMINAL CIRCUITRYExaminersPrimary: Dwyer, James L.Attorney, Agent or FirmInternational ClassesH04M 1/70 (20060101)H04M 1/68 (20060101) H04M 9/02 (20060101) H04M 3/16 (20060101) AbstractThis invention is a telephone privacy protector to be interposed between a common exchange line and each one of at least two telephones sharing the line. The device includes a voice connecting circuit connected between a respective phone and the line; a control circuit operatively engaging the connecting circuit, and having an on- and an off-state, and a trigger having a threshold voltage responsive to the line voltage controllingly engaging the control circuit to trigger it into its on-state to provide a voice connection between the telephone and the common line in response to the line voltage exceeding said threshold voltage. | |
