Abstract: An improved voice security system wherein the improvement resides in a non-electrical contact between a remote signalling apparatus and the standard microphone of a two-way radio so that voice transmissions may be accomplished in response to the sensing of a predetermined condition by sensors operatively connected to the remote signalling apparatus. The non-electrical contact is accomplished by the use of a voice and key unit which is electrically connected to the remote signalling apparatus and having a microphone holder mounted thereon whereby the standard microphone physically contacts the housing of the voice and key unit. A speaker is mounted within the voice and key unit housing, and the microphone is modified to include a reed switch which is actuated by a coil placed within the voice and key unit housing whereby, upon applying electrical energy to the coil, the reed switch will close to permit the microphone to transmit audio messages generated by the remote signalling apparatus.