Abstract: A compact color monitor device that utilizes active and passive magnetic shielding to eliminate the visible distortion of color displays due to externally-imposed magnetic fields. The color monitor device can be installed in standard 19-inch EIA rack enclosures used on-board surface vessels and remain operable with no color distortion when the vessel is subjected to .+-.5 Oersted degaussing fields. The color monitor device includes a quick-degaussing circuit for degaussing internal components in approximately 1/60 of a second.

Abstract: The present invention describes a method and apparatus for selectively transmitting information by radio, without causing congestion of transmission frequency bands, even if the number of users who may be called is relatively great. This object is achieved by ensuring the identification of the users by a decoding matrix provided in each of the receiver devices assigned to each of the users; the pulses characterising a call code are introduced into a shift register and compared with the decoding matrix; when the corresponding binary words are identical, the call signal of the receiver is sent whether it is a sound and/or like call, also the shift register is used to record the details corresponding to the information to be transmitted and then to present said information in alphanumerical form.