Abstract: A digital data radio transmission system, such as may be used in communicating point-to-point by radio, in which a keyboard is used to insert a multi-decimal-digit number representing the called station. This is fed to a decimal-to-binary converter, forming a train of binary bits which are then coded in a selected manner so as to be substantially noise immune. The output of the coder then goes to the radio transmitter. At the receiving end, a similar means is provided for obtaining and storing in a 24-bit register the selected number of the called station. The output of the radio detector is then decoded to obtain the 24-bit word representing the called station, which is stored in a second register. A comparator compares the numbers stored in the two registers. When they compare positively, an alarm signal is enabled, or the receiver squelch is broken.

Abstract: An automatic loader-unloader of cassettes to and from a videotape deck in which the unloader comprises means to tilt and support the videotape with its top surface at a selected angle to the horizontal, and providing a shelf in front of the deck with the shelf co-planar with the top surface of the deck. Loading means are provided by means of an arm mounted above and parallel to the deck surface with means adapted to press against the back edge and top surface of the cassette when mounted on the shelf, so as to provide two components of force, one parallel to the plane of the cassette, causing it to move off the shelf and on to the elevator plate of the tape deck, and a second force perpendicular to the surface of the cassette so that when the deck is positioned on the elevator, and extends the eject spring, the downward force will cause the elevator to move downwardly and into the recording position.