System and method for fiber optic communication with safety-related alarm systems

摘要

A system and method for monitoring and safety related systems (SRSs) in a Secure Compartmented Information Facility (SCIF) that addresses concerns for security of electronic emanations from equipment in the SCIF. A fiber optic link connects an optical receiver located within a SCIF and an optical transmitter located outside the SCIF. Alarm signals generated by an SRS located outside the SCIF are detected and sent to the optical receiver over the fiber optic link. The optical receiver converts the optical signals to electrical signals and directs the signals to alarm devices within the SCIF. Additionally, an audio signal generated at the location outside the SCIF is converted to an optical signal and then reconverted to an audio signal by the optical receiver for broadcast over a speaker located within the SCIF. A tone signal generated at the optical transmitter is continuously sent over the optical fiber link to the optical receiver and the SCIF speaker. The tone signal is monitored and any loss of the tone signal at the speaker causes an alarm signal to be returned to the optical transmitter located outside the SCIF. The optical receiver located within the SCIFF monitors an alarm device within the SCIFF for the presence of an alarm condition within the SCIFF. If an alarm condition within the SCIFF is detected, an alarm signal is sent over the fiber optic link to the optical transmitter located outside the SCIFF and directed to the SRS located outside the SCIFF.