The Contemporary Research RF-AB RF Switch is a self-terminating remote controllable RF A/B switch. When used with the 232-ATSC+ HDTV Tuner, the RF-AB will automatically switch between Air and Cable RF feeds. The included 3.5 mm cable connects the RF-AB to the A/C jack on the back of the tuner. As a general-purpose RF A/B switch, the RF-AB correctly handles RF signals by terminating the RF feed when it is switched off. In addition, the switch will default to the Cable input when there is no DC power.