Abstract: A digital cordless telephone apparatus comprising a microprocessor based battery powered portable handset unit and a microprocessor based stationary base unit which each transmit and receive digital voice data and digital command data to and from one another over multiple RF channel frequencies in the 902-928 MHz band, is disclosed. The user's voice is digitized, scrambled and modulated for transmission and upon reception, the modulated digital voice data signal is demodulated, descrambled and decoded. A command data--voice data interface inserts command data packets into the stream of digital voice data prior to transmission and locates and captures command data packets from the incoming stream of received digital data. A silence sequence replaces the captured command data packet such that no audible sound is heard by the user.

Abstract: A digital cordless telephone apparatus comprising a microprocessor based battery powered portable handset unit and a microprocessor based stationary base unit which each transmit and receive digital voice data and digital command data to and from one another over multiple RF channel frequencies in the 902-928 MHz band, is disclosed. The user's voice is digitized, scrambled and modulated for transmission and upon reception, the modulated digital voice data signal is demodulated, descrambled and decoded. A command data - voice data interface inserts command data packets into the stream of digital voice data prior to transmission and locates and captures command data packets from the incoming stream of received digital data. A silence sequence replaces the captured command data packet such that no audible sound is heard by the user.

Abstract: An audio signal expander apparatus for integration into a satellite receiver for recovering audio signal transmissions carried by satellite services utilizing compressed audio signal transmission processing wherein the incoming audio signal is expanded by a ratio which varies with both the audio signal amplitude and audio signal frequency. The audio signal passes first through a low-pass filter and then through a frequency selective negative feedback circuit the output of which is filtered and de-emphasized. In addition, the level of the output audio signal may be varied by a level control adjustment.