Toitevõrgu sidesüsteem (MCS) on andmete edastamine juhi (elektriliinikandja) kaudu, mida kasutatakse samaaegselt ka vahelduvvoolu elektrienergia edastamiseks.
Mains communicating system (MCS) is the carrying of data on a conductor (the power-line carrier) that is also used simultaneously for AC electric power.