| 摘要 |
A tamper-indicating transmitter is disclosed that indicates a subsequent tamper event during a tamper alert period, T, which is initiated by a first tamper event. In a preferred embodiment, the transmitter includes a transmitter housing having a conductive strap attached thereto for securing the transmitter about a confinee's limb, the confinee typically participating in a home arrest program. Within the housing, a clock source generates pulses having a period t that are input to a counter whose reset line is connected to the conductive strap. When the conductive strap is opened, the counter is held reset and its output is a predetermined multiple bit maximum. Upon the closing of the strap, the counter counts the clock pulses and decrements the counter output from the initial predetermined maximum count down to a predetermined minimum count which remains on the counter output if no subsequent opening of the strap occurs. The counter output is combined with an identification code and is serially provided to a digital/RF converter which transmits a data message containing the counter output and an identification code to a monitoring unit that relays the status of the transmitter to supervisory personnel at a central monitoring station. The counter output is used by the monitoring unit to compute a time a strap closure so a tamper by the confinee during the tamper alert period following securement of the transmitter to the confinee can be distinguished from the strap opening and closing at the transmitter installation.
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