Remote services are widely used in industry for control, operation, diagnosis and maintenance. In almost all sub-domains of automation and control, solutions for remote access of devices, machines and systems are established. Since coining the term teleservice more than three decades ago, most of the work has rather focused on specific technological solutions than on the general tasks and requirements. In this paper, general requirements and concepts for remotely accessing devices, machines and systems are presented. For this purpose, a domain analysis method has been employed to capture the knowledge from different domains related to remote services.