Patent US 8,976,874

In a modular signal mirroring system each point-to-point RF transceiver end has a controller module coupled to one or more I/O modules. The I/O modules have various input and output circuits. A signal received at the near end is reconstructed at the far end after being transmitted in an RF packet. The reconstructed signal may be the same as the input signal, inverted from the input signal or level-shifted from the input signal. It is representative of the input signal following the input signal's state after a time-quantization latency. Transmission between the two ends is via a periodic transmission controlled in a master slave protocol. If a transmission is not received in a timely manner or, in some systems, if intentional interference with transmissions is detected, the reconstructed signal is forced to a safe state determined by local switch settings. The settings include the last known good state.