Our HDMI to RF Coax Adapter allows you to convert digital signals from an HDMI source to VHF analog TV signals. Allows you to watch videos and play games on channel 3 or 4 on older TV models (CRT) and other non-HDMI devices. This device does NOT work in the reverse direction (connecting an old coax video source to an HDMI-input television). UL-Listed AC Adapter. The source device that is connected to the HDMI input on this product must be able to output a 480i/480p signal.