Handset Amplifier (430-0237) Operation Faxback Doc. # 15599 A 9V battery (not included) is required for power. Remove the back cover with a coin and snap the battery connector over the battery. Press the cover back into place. Disconnect the modular plug of the handset from your phone. Connect the DUoFONE modular plug to the handset jack on the base of your phone. Then connect modular plug from the handset to the DUoFONE's modular jack. The DUoFONE amplifier is automatically activated when you answer your phone. Now simply adjust the VOLUME and TONE controls. NOTE: If sound becomes weak or distorted, try a new battery. NEVER leave a weak or dead battery in your DUoFONE. Leaking batteries may cause damage to the unit. If the unit won't be used for a few months, remove the battery. A phone cannot be modified for a modular handset connector. If your phone does not have them, you can not use this device. (ALL-06/12/95)