Electronic data recorder for electric energy metering

摘要

An electronic remote data recorder records pulses representing usage of a commodity such as, for example, water, gas or electricity from a plurality of consumers. The data from each consumer is stored in a respective data storage device. Each data storage device is associated with an interval data directory which stores the times at which significant events, affecting the data in the data storage device occurred. Thus, the data in the data storage device is compact, without requiring a contemporaneous time code for each data item. Data integrity is retained over a period of power outage in a non-volatile storage device. Initial, post-installation programming is enabled by comparing the data pattern in the non-volatile storage device with a predefined data pattern that is expected to exist once the apparatus has been programmed. A write-protect switch prevents programming during an incoming call after the initial programming. Programming from an external source may be permitted during a telephone call initiated by the data recorder itself. A telephone line-sharing device permits a plurality of remote data recorders to share a single telephone line without interfering with each other.