The AD903 is powered by the intercom system and requires no batteries or separate power supply. | The AD903 connects to the intercom circuit just as a beltpack does, through a rear panel 3-pin XLR. | Access to the input and output are via a rear panel 4-pin XLR. Pins 1 and 2 are input and pins 3 and 4 are output. | Both the input and the output are transformer isolated from whatever devices are connected. The wide range of level adjustments will accommodate almost any audio signal.

Powered by MS301 to which it is attached | Does not increase amount of current available, only the number of independent communications circuits | The Status Bar of LEDs indicates that the unit is receiving its 24 volt operating current from the MS301 (green), and the trouble status of any of the circuits (red) | On the rear panel there are DIP switches to allow you to choose between ducking and muting the program audio in the IFB mode, and for lifting the termination circuit of each circuit individually | The MSM301 automatically maintains the 200W termination impedance when linking, but there may be applications where one of its circuits is connected differently