Abstract: A signpost (11, 241-256, 322, 612, 623, 626-628, 652, 661, 682, 686, 703) transmits low frequency signals to a beacon tag (12, 271-275, 301-316, 395-397, 616-618, 641-643, 653, 656-657, 662-664, 679, 708, 711), which in turns transmits high frequency signals containing a signpost code from a received signpost signal to a reader (13, 261, 319, 521-530). The signpost can be mounted on one mobile device and the beacon tag on another mobile device, in order to determine when those mobile devices are in close proximity. Further, a sensor (32) can be provided to detect the presence of a mobile device, and to cause the signpost to change the signpost code in its transmitted signals.

Abstract: An improved retractable tamper resistant annunciator that can be mounted flush in a supporting structure is described. The annunciator mechanism includes a housing that has an actuatable cover. Signaling devices are enclosed within the housing, and can be selectively actuated when the cover is opened. A mechanism to open and close the cover to expose the signaling devices or to cover the signaling devices include a reversible motor structure. Alternative mechanisms to open and close the cover include biasing structures to move the cover in a first direction and an electrical device to move the cover in a second direction.

Abstract: A pull box for an emergency alarm system is disclosed having a modular construction that accommodates one or more optional modules in order to provide a wide variety of possible configurations. Also, the basic design of the pull station provides for its resetting without requiring a cover of the pull station to be open. As part of the optional modules, the pull station may be configured to provide both local and general alarm signals, with the general alarm signal capable of being activated only by authorized personnel.

Abstract: An improved driving method capable of achieving high-quality display even in simple matrix addressing for a ferroelectric liquid crystal matrix panel at a high multiplex ratio applies pulses of a frequency higher than that of a scanning voltage in an addressed condition to a scanning electrode in a non-addressed condition to gain either a surface stabilizing effect or an AC field stabilizing effect, hence ensuring high-contrast display. And the panel is so driven that the temporal average of the voltage applied to each pixel becomes zero, thereby averting deterioration of the liquid crystal.

Abstract: In order to pull a fire alarm door to actuate an alarm, a complimentary door must first be pushed in so as to permit an operator to pull the fire alarm door.

Abstract: A location transmitting system for use by one or more guards in a security system. Encoders are located at predetermined reporting locations which have no power supplies. Each guard carries a walkie-talkie radio transmitter which he places in a receptacle at the reporting location, energizing the encoder through external terminals in the receptacle which mate with external terminals of the walkie-talkie and its power supply.