The 5600ACO/ACO2 Automatic Changeovers are intended for use with two 5600MSC Master Clock/Sync Generators. The 5600ACO/ACO2 system uses latching relays to ensure maximum reliability and minimal disruption in the event of any failure. The complete system provides the highest level of security for television station video and time synchronization systems. The 5600ACO is a 1RU device which is an ACO for a subset of the 5600MSC outputs. The 5600ACO2 is a 2RU ACO for all outputs of the 5600MSC. Two power supplies are included as a standard feature, to alleviate any single point of failure concerns. The front panel has three switches, recessed into the panel for added security. There is an AUTO/MANUAL switch, a GPI/FRONT PANEL switch, and an A/B select switch for manual changeover. In automatic mode, all signals from both 5600MSCs are monitored to detect any abnormal signals. For example, if a level, pulse width, phase, time code error, or other abnormality is detected, the 5600ACO’s circuitry will trigger and the entire bank of signals will be switched to the backup 5600MSC. In manual mode, the changeover can be operated from a GPI or from the front panel switch. LEDs provide status information as to the health of the two 5600MSCs, together with an indication as to which one is active. In addition, two GPO outputs indicate which master is active and when the inputs from both masters are not the same. The 5600ACO2 features selectable voting via VistaLINK® for auto changeover features. Individual inputs may selectively be included or excluded in the voting process to drive auto changeover logic (a feature only available on the 5600ACO2 model).