Abstract: Procedure to transmit data, especially data used to operate and observe a system in which a request to build up a transfer channel to a web server is sent from a web client, comprising the following properties: a message that demands a connection to build up a first transfer channel is sent to a web server from the system that needs to be watched or operated; this request stays open and thus creates a tunnel for data transfer between system and web server; at least one additional channel of transfer is generated while the web client requests connection between client and web server; the client establishes contact with the system via the data transfer tunnel in order to send and receive reference data bi-directionally.