For TwinBus door intercom systems. Intelligent hands-free calling. Extra flat design, only 23 mm high. Differentiation between door and floor calls. 5 melodic ring tones. Volume adjustable in 4 levels. Call mute switch. Door opener button. Light switch function via switching device. Dimensions: 90x152x23 mm (WxHxD). Accessories: ==>Flush-mounted and hollow wall installation with flush-mounted frame 17322..
