METHOD AND APPARATUS TO PROVIDE DIGITAL SIGNALING WITHOUT INTERNAL MODIFICATION OF ANALOG FM TRANSCEIVER

摘要

An external speaker/microphone apparatus for a radio transceiver includes a speaker, a microphone, a push-to-talk switch, and an emergency switch. The apparatus further includes an encoder module operatively coupled to the push-to--talk switch and the emergency switch and configured to generate a digital identification each time the push-to-talk switch is pressed, and a digital emergency signal and digital identification when the emergency switch is pressed. The apparatus also includes a connector configured to operatively couple audio to the speaker from the transceiver, a combination audio signal from the microphone and the encoder module to the transceiver. The connector is further configured to operativel y couple the push-to-talk switch and the emergency switch to the transceiver so that the transceiver is switched to a transmit mode when either the push-to-talk swit ch or the emergency switch is pressed.