The present invention provides an efficient and simple method and system for providing a customer with a service on demand.The invention is based on providing a plurality of interconnected technical devices with remote access. During operation of a technical installation including the technical devices, operating data are acquired, encrypted and stored in a operation database. Upon an explicit service request by the customer, at least one of the technical devices sets up a remote connection to a service center, preferably by using a smart card including Public Key Infrastructure (PKI) data for validating the smart card, where the remote connection is verified and the encrypted data stored in the operation database are read out and decrypted. Based on the decrypted data--which represent a current status of the technical installation--, a service activity is efficiently performed at the technical installation, either remotely or locally.