Aiphone DB-1SD Hands-Free Sub Master Station

Aiphone DB-1SD Hands-Free Sub Master Station Part Number: DB-1SD Manufacturer: Aiphone UPC Number: 790143325824 Description Aiphone DB-1SD Hands-Free Sub Master Station Hands-Free Sub Master Station The DB-1SD hands-free sub station features a calltone volume control with mute indicator, receive volume control, AllCall button, Talk button, and Off button.  It connects via 4 wires tothe DB-1MD master station.  Up to 4 sub stations can be added to thismaster and communication is possible between the 5 total stations viathe All Call button