The 500ACO2-HD/SD dual HD/SD Autochangeover is designed to provide extension to the 5600ACO for HD or SD SDI, DVB-ASI, AES audio, bi-level/tri-level syncs and NTSC/PAL video. The unit can also be operated as a standalone changeover unit with two independent 2X1 switchers. The 500ACO uses latching relays to ensure maximum reliability and minimal disruption in the event of any failure.