Set Containing: DA-4DS, 4 x DB-1MD & 2 x PT-1211C: DA-2DS is a silver door station that connects via two wires to 4 master DB-1MD. System power is the PT-1211C. The DA-2DS features a 12V AC output for door strike connection, call button and illuminated directory. The master handset DB-1MD features a call tone volume control, handset for communication and button for door release.