Abstract: A method and apparatus for reducing the echo in a hands-free digital cellular communications system is presented. Acting upon speech signals being present in the downlink, uplink speech frames generated by the hands-free communication device are attenuated to prevent the downlink speech signals from being transmitted at full volume back on the uplink as an echo. Added to the attenutated uplink speech frame is a noise frame generated by the hands-free communication device, which provides a consistent level of background noise to the person at the other end of the call. The noise codeword is further randomly ordered to prevent any modulative effects from the process.

Abstract: The present invention provides a battery-powered radio transceiver for transmitting and receiving digital signals and method of operation for reducing electrical power consumption and thereby improving battery life between recharges. The radio transceiver includes an operator interface and a transmitter, electrically connected to a microphone in the operator interface, to convert speech signals into digital radio frequency (RF) signals for transmission. A receiver is electrically connected to a speaker in the operator interface to receive digital RF signals and to convert the RF signals into audio signals from the speaker. A microprocessor electrically connected to the operator interface, the transmitter and the receiver controls the operation of these components in processing telephone calls. An electrical storage battery is electrically connected to the microprocessor to supply electrical power to the microprocessor, the operator interface, the transmitter and the receiver via the microprocessor.