A power line modem interface includes a modem that modulates an RF signal with digital data and demodulates an RF signal to recover digital data. A filter is connected to the modem and to a DC power line that supplies power to a local power supply. The filter couples the RF signals from the modem to the DC power line and filters the RF signals out of the local power supply. The filter includes: a first inductance connected to a hot side of the DC power line; a second inductance connected in series with the first inductance and connected to the local power supply; and a capacitance with a first plate connected between the first inductance and the second inductance and a second plate connected to the modem so that the RF signal is passed between the modem and the DC power line.