A system having transmitters, receivers, transceivers, actuators, sensors, input/output rack, and/or a computer with application specific software and/or hardware, for secure communication and control. The system may use frequency hopping spread spectrum (FHSS) and encryption. Schedules for FHSS and encryption keys may be varied in variously elaborate ways. The system may utilize a distributed control system to manage the transmission and reception of signals, control operations, FHSS scheduling, changing of keys, and information.