The MS-2002 is a complete 2-channel master station and system power supply (24VDC, 2Amps total power) in a single unit. Simply plug it into any AC power outlet from 100 to 240 volts, add a microphone or headset, connect intercom stations to the back panel, and you’re ready to communicate. It has both 1- and 2-channel connectors, so you do not have to add a separate breakout box if you want to mix 1- and 2-channel stations.