This slim surface-mounting internal video unit with colour screen is standardly equipped with the following functions: allow a conversation with a visitor, produce a different tone for a call at an apartment door, an internal call and main door calls from two different external video units, switch lights on and off, open doors, adjust the volume, switch off the ringtone, indicate a busy signal and call signal with LEDs, transmit a control function, allow a parallel call, make an internal call, etc. The controls consist of clear, intuitive touch buttons. The communication with the visitor is hands-free. The device can be entirely programmed using the Niko configuration software for access control.