Sound Carriers in the Form of Magnetic Tape, Sound Carriers in the Form of Optical Tape Either of the Variable Density or the Variable Amplitude Type, Sound Carriers in the Form of Grooved Record Discs, Automatic Play Back Machines-Namely, Master Units and Slave Units, Relay Networks for Transmitting Sound Representing Signals from a Central Transmitting Station to One or Several Remote Sound Reproducing Stations-Namely, Loud Speakers, Tape Duplicators and Cassettes for Storing Reels of Tape

Flight simulators