Abstract: An aircraft control and display system having a multifunction display for configuring the vehicle flight parameters and control of mission equipment utilizes a dedicated alphanumeric display as a scratchpad memory for temporarily displaying IFF mode commands encoded in alphanumeric form and for changing an IFF transponder code, thereby obviating the use of the multifunction display and the need thereby for reprogramming the mission functions. Codes entered in the alphanumeric display are validated against codes stored in a master control processor unit, whereby a prompt is provided to the operator to reenter the code in the event of an error in entry or an invalid code.

Abstract: Apparatus for transferring RF signals between a plurality of inputs and a plurality of outputs comprises a plurality of output multiplexers 30.sub.1 . . . 30.sub.10, each made up of a plurality of hybrid/tunable filter combinations 21.sub.1 . . . 21.sub.8. The RF signal inputs of the apparatus are supplied to one output multiplexer 30.sub.1 and the inputs of each output multiplexers are connected to the inputs of the adjacent multiplexer, such that a signal not transmitted by one output multiplexer will be passed to a next output multiplexer, and so on. By appropriate tuning of the filters 24 in the output and multiplexers the RF signals may be reconfigurably distributed between the inputs and the outputs, and, the need for switching is avoided while maintaining an acceptably low path loss.