Abstract: An electricity meter which, in one embodiment, includes a detection circuit, or unit, coupled to the meter microcomputer and supplies a detection signal to the microcomputer indicative of the data source is described. Using the signal supplied by the detection unit, the microcomputer can determine whether to allow access to metering data and other data stored in the meter. In an exemplary embodiment, the detection unit has three different modes, or states, of operation. These states of operation are sometimes referred to as the steady state, the optical port data transmit state, and the option board connector transmit state. The steady state refers to the condition of the unit when no data is being transmitted to the meter microcomputer from either optical port or the option board. In the steady state, the detection signal supplied to the microcomputer is high. In the optical port data transmit state, the detection signal transitions, as least momentarily, from a high state to a low state.

Abstract: An electricity meter which, in one embodiment, includes a microcomputer coupled to both a liquid crystal display (LCD) and an optical port. The LCD includes an on board controller and an LCD random access memory (RAM), and in accordance with the present invention, the microcomputer is programmed to communicate the contents of the LCD RAM to the optical port during selected times of meter operation. Generally, and in an exemplary embodiment, when the LCD RAM data is updated by the microcomputer during meter operation, the microcomputer communicates such updated data to the optical port. In one specific implementation, a user selectable flag may be set to 1 or 0. If the user sets the flag to 0, then the communications feature is not enabled. If the flag is set to 1, then the communications feature is enabled. In operation, and upon receipt of a display quantity command, the microcomputer writes data to the LCD RAM. The microcomputer then checks whether the communications feature is selected (i.e.