Cei Iec 62056-21 -

: It specifies the use of an optical interface (using infrared light) or electrical interfaces like RS-232 or RS-485. The optical port is particularly iconic—the small circular "eye" found on the front of most digital meters. Operational Modes :

: Millions of meters currently in service rely exclusively on this protocol. CEI IEC 62056-21

The CEI IEC 62056-21 Standard: Powering Local Meter Data Exchange : It specifies the use of an optical