Fiberplex TDU-4000 Telephone Disconnect Unit

The Fiberplex TDU - 4000 is a top - notch telephone disconnect unit designed to safeguard your privacy. It protects your phones from being misused as secret listening devices. When the phone is on - hook, it electrically disconnects the telephone line from the phone. The line stays open, and the phone's voice path is grounded, stopping room audio from being sent over the line and preventing eavesdropping. The phone only connects to the line when off - hook. The 'Off Hook' and 'Ring' detect signals are opto - isolated from the phone. A typical setup has one TDU - 4000 linked to the POTS line and the subscriber's phone. For high - security needs, FiberPlex suggests 'R' units as they have extra shielding and filtering to suppress RFI. Key features include preventing signal propagation to the Central Office or PBX when the phone is on - hook, and it's compatible with standard phones, STU - III phones, fax machines, and modems. Technical specs: Power requires a voltage range of 7V (min), 9V (typical), and 12V (max), with a supply current of 525mA. Audio has an input level of 5 dBm, a load impedance of 600 Ohms, and a frequency response of 200 - 8k Hz (±3 dB). It can be stored at - 40 - 85 °C and operated at 0 - 70 °C, and uses an RJ - 11 interface connector.

Using the Fiberplex TDU - 4000 is easy. First, connect it to the POTS line and your phone using the RJ - 11 connector. When you're not using the phone (on - hook), it automatically disconnects the line to protect your privacy. When you pick up the phone (off - hook), it connects normally. Make sure to use a power supply within the voltage range of 7V to 12V, with a typical 9V supply. Don't expose the unit to temperatures outside the storage range of - 40 to 85 °C or the operating range of 0 to 70 °C. For high - security applications, consider using the 'R' units. Keep the unit clean and free from dust. If you have any issues, check the power supply and connections first.