Systevo Control, surface mount design, as a control unit for an organizational unit such as a ward or living area. It is a modular central control unit with two slots for the optional field bus cards (FBC). There is an option to provide power redundantly via a decentralized power supply installed in the ward or living area. It monitors and synchronizes all data traffic and intercom connections (conversations, announcements) within the organizational unit and coordinates communication with other central control units via IP communication (zone data bus or ETH-LAN). In addition, it controls display screens and acoustic call messages in accordance with stipulated priorities / service (zone linking) within a system. It has flexible configuration options for types of call, groups, services, general announcements, display texts, device parameters, system language, etc. depending on customer requirements, via the server (PC) with a comfortable Windows GUI. It uses a maximum of 64 central control units with up to 250 logical groups (sub-groups). Networking is implemented via the ETH-LAN IP interface (data / audio) and the optional zone data bus POF (data / audio). It includes an integrated gateway function for forwarding data / audio signals from the upstream bus interface (ETH-LAN, zone data bus) to the corridor data bus. It supports the compatibility mode for existing system installations with the zone controllers 72660x; a firmware update of the basic systems installed may be required. A master control unit (in the case of Ethernet: without corridor data bus) is set up to communicate with the upstream server via ETH and to control the escalation of all system alerts within the entire system. It is prepared for future firmware updates subject to license and equipped with an SD card slot to enable the use of additional service features. It is installed centrally or decentrally (surface mount design) in environments pursuant to environmental category I. Project specific planning of central equipment is required for more than 500 rooms.