smrt mtr s n lctrnc dvc tht rcrds nfrmtn—sch s cnsmptn f lctrc nrgy, vltg lvls, crrnt, nd pwr fctr—nd cmmncts th nfrmtn t th cnsmr nd lctrcty spplrs. Sch n dvncd mtrng nfrstrctr (M) dffrs frm tmtc mtr rdng (MR) n tht t nbls tw-wy cmmnctn btwn th mtr nd th spplr.