| 摘要 |
A telephone-based automatic meter reading (AMR) system includes a telemetry device through which a host computer can collect meter readings remotely. The telemetry device has one or more ports to read one or more meters at pre-scheduled time intervals. All data read from the meter(s) is stored in a non-volatile memory in the device, and the collected data is transferred back to the host computer according to a predetermined schedule (with a call back interval that can be hourly, daily, weekly or monthly). An apparatus and method is provided which enables the host computer to initiate a special data stream to invoke a powerless circuit portion of the telemetry device-specifically, a telephone-side portion which is electrically isolated from the meter-side circuitry (such as by an optocoupler). The ringing signal on the phone line powers the circuitry in this telephone-side portion of the device such that no AC connection or separate battery power is required. Once the telemetry device receives the special data stream, it ignores the regular call back schedule and calls back to the host computer immediately when the shared telephone line is available.
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