For TwinBus door intercom systems with internal voice communication. For TwinBus door intercom systems. Extra flat design. Optical call display / night design. Volume adjustable in 4 levels. 8 melodic ring tones including 3-tone gong: call mute switch. 1-man commissioning. Buttons for 8 internal subscribers and 8 TwinBus switching commands. Call differentiation for door/floor/internal call: call memory for internal calls. Automatic door opener. Door opener button. Light switching function via switching device. Dimensions: 132x220x42 mm (WxHxD). Accessories: ==>Flush-mounted and hollow wall installation with flush-mounted frame 17321..