Non-vital turn off of vital output circuit

A vital information processing system adapted for railway signaling and control operations and having means for detecting the state of the outputs therefrom, comprising:

• a vital energy source;
• a vital processor including (a) a processing means and (b) at least three output ports and an input port forming part of said processor means, and in which a first of said output ports provides a non-vital on/off operation, and a second output port of said output ports provides a vital on/off operation;
• and
• means for optionally shutting down the entire system, involving all outputs, or shutting down a selected output device, thereby to improve the overall system availability, said optionally shutting down means including:
• a non-vital power control having a first input connected to said first output port and having a second input connected to said vital energy source;
• and
• a vital output control having a first input connected to said second output port, having a second input connected to said third output port, and having an output connected to said input port;
• and said vital output control having a third input connected to an output of said non-vital power control.