Abstract: An automatic disconnect device with a protected ringer for providing a secure telephone system, the device being interposed between the telephone company outlet and a modified telephone set. The device generates its own audible tone burst only when a standard ring signal is generated by the telephone company and is designed so that no ambient sound can be transmitted back to the telephone outlet. An on-hook/off-hook detector is incorporated in the device to determine when the handset has been lifted off-hook. If off-hook, the telephone operates normally. In the on-hook status, or position, the telephone is automatically disconnected from the telephone outlet at all times. A visual indication is provided when the telephone is on-hook. The incoming telephone company lines from the outlet are conditioned by filters within the device such that the device is not affected by signals other than normal telephone signals.