A battery operated cable security seal for cargo containers and the like
includes a housing with a transparent cover for visual inspection of
illuminated internal green or red LEDs, the red LED representing a
tampered state of a stranded metal locking cable, which has a length
sufficient to secure the keeper bars and hasp of a cargo container door.
The cable has an internal conductor whose conductivity, e.g., resistance,
manifests a tampered condition when severed and also if reattached, e.g.,
by a solder or spliced joint and so on. The electrical continuity of the
conductor is monitored by a circuit in one embodiment for a severed
state, i.e., tampering, and whose resistance is monitored in a second
embodiment correlated optionally to either or both ambient temperature
and a battery output voltage. The seal housing has two compartments one
being hermetically sealed and contains the circuitry and the other
containing a cable locking device for receiving and locking the cable to
the seal. The circuit includes an RFID tag which may be part of a mesh
network configuration with other tags.