Abstract: A passive dual polarization unit and coherent transceiver and/or receiver including one or more passive dual polarization units are provided. An example passive dual polarization unit includes a polarization splitter configured to split an input signal into a TE mode and TM mode signals; TE/TM splitters each designed to split the TE/TM mode signals into first TE/TM signals and second TE/TM signals; a first TE signal polarization rotation component for receiving the first TE signal and providing a third TM signal having the same magnitude and time dependence as the first TE signal; a first TM signal polarization rotation component for receiving the first TM signal and providing a third TE signal having the same magnitude and time dependence as the first TM signal; and TE/TM couplers that couple the second TE/TM signals and the third TE/TM signals to generate output TE/TM signals.

Abstract: A passive dual polarization unit and coherent transceiver and/or receiver including one or more passive dual polarization units are provided. An example passive dual polarization unit includes a polarization splitter configured to split an input signal into a TE mode and TM mode signals; TE/TM splitters each designed to split the TE/TM mode signals into first TE/TM signals and second TE/TM signals; a first TE signal polarization rotation component for receiving the first TE signal and providing a third TM signal having the same magnitude and time dependence as the first TE signal; a first TM signal polarization rotation component for receiving the first TM signal and providing a third TE signal having the same magnitude and time dependence as the first TM signal; and TE/TM couplers that couple the second TE/TM signals and the third TE/TM signals to generate output TE/TM signals.

Abstract: A system for monitoring events which is capable of automatically configuring itself responsive to changes in system hardware comprising: a plurality of input circuits for detecting events and a plurality of output circuits for indicating the presence of the events; a computer means, including a microcontroller connected to the input circuits for two-way communication with the input circuits and further connected to the output circuits; a front panel and means at the front panel for further indicating the events; and means within the computer means for automatically configuring the system responsive to changes in system hardware.

Abstract: A color graphics terminal for monitoring a system in which a graphics monitor is connected to a computer, the graphics and at least two separate graphics windows which are capable of representing simultaneously two geographically, hierarchically related graphic displays of the system, with an arrangement for controlling the computer to automatically display on the graphics monitor the related graphic displays in response to certain inputs received by the computer.

Abstract: A communication system in which a controller is coupled over a communication path with two or more transponders, at least two of which transponders have different addresses, which controller and transponders communicate by periodically transmitting a broadcast message simultaneously to all transponders, transmitting an acknowledge message indicative of a new input received by at least one of the transponders, and individually polling all of the transponders using a polling technique which incorporates time periods to allow communication between the controller and a selected transponder, wherein the polling is only activated subsequent to the transmission of the acknowledge message. Periodic polls of all transponders in sequence provide supervision of the integrity of the system.