This thesis describes work on the development of a `plug and play' communications system for ethernet designed to enable devices to automatically provide data logging and control services over a network. Examination of the current work in protocol design such as Common Object Request Broker Architecture (CORBA) suggests that there is scope for research in developing a simpler design. This view is supported by examining the factors that have led to the widespread adoption of the Internet and its protocols. The approach is to develop a protocol that is open systems based. The protocol will allow multiple applications to be served; one of these applications will be to enable numerical controllers to download programs over the Internet. The research carried out here involves developing a standard `plug and play' communications protocol for ethernet based on TCP/IP. A pre-requisite for developing such a `standard' protocol is that of universal interfacing. In view of the fact that devices do not share common interfaces a universal electronic connector box has been developed. The purpose is to provide connectivity to a wide range of devices. The development of the electronic box involved building successively complex prototypes. The prototypes are designed to control and transfer information to and from equipment such as printers, photocopiers, electronic door access and numerical controllers. By building such a diverse range of `real world' applications it is possible to show how a single technology can control dissimilar devices. The development of the technology has the potential to enable SME's to replace complex personal computer based control systems with simple Internet enabled `plug and play' controllers. By sharing common functions and data services the technology also creates new opportunities for SME's to develop supply chain management and enterprise resource planning systems. The results of the research have led to the design and implementation of photocopier and printer control management systems, as a test of the validity of the protocol and prototypes that have been developed. The printer and photocopier control management systems are now in daily use by staff at the University of Teesside. The numerical machine control system has attracted government funding for further development.