Yes, the ACD has two plugs with independent inputs for the power supply. Voltage may and should be connected to both plugs, these may also be different mains/voltages, e.g. from different batteries.
In this case, the ACD is supplied by both voltage sources in parallel. Internally these are decoupled, so that this is always harmless. The current is used by both sources in parallel.
This way you can easily build a redundant supply. If you have e.g. radio and transponder each connected to one plug of the ACD, in case of failure of one system the other can still be used. So, for example, if the transponder's fuse blows due to a broken cable, the radio can still be used.
The source with higher voltage is used for voltage indication (Menu -- Device --Status -- Supply Volt).