Indoor station for hands-free operation of the TCS:BUS. Intuitive control of main and secondary functions via differentiated buttons. Large offset blue door opener button. Large offset voice button. Light button. Factory-assigned control button: permanently assigned to control function. Logout button to disable the ringtone with visual indication. Visual indication and short-term storage of door calls. Visual busy indication during an active voice connection. Selection of 13 ringtones, adjustable by the user. Ringtone volume adjustable in 8 levels by the user. Voice volume adjustable in 8 levels by the user. Acoustic and visual call differentiation between 2 front doors, apartment door, and internal calls. 1 parallel call with adjustable service device. Audio privacy function and automatic call disconnection. The lower housing half with a mounted screw connection can be pre-installed and alternatively equipped with the sister model door phone. The configuration software configo can be used for comfortable system configuration on a PC with automatic detection of device type and serial number. Acoustic and visual error indication for time-saving commissioning. Functionally expandable through installation ducts for call relays and control of the radio signal. For surface mounting, mounting over a flush-mounted box, or table mounting with a table. Accessory ZIT3030-0010. Signal transmission and power supply via polarity-free and short-circuit-proof 2-wire TCS:BUS. Audio and video indoor stations can be combined within a system. Energy-efficient due to low standby consumption of only 0.025 W. 2-wire technology: modernization-friendly, 3-wire technology possible. Tested according to EN 50486.