This paper presents a computer-supported desk-co- desk information exchange system which allows two users to conduct a multimedia information transfer. Participants can jointly view and edit a piece of shared multimedia information, including text, graphics, images, and voice, which is transferred through a local area network. The system includes a talk system combined with voice and text, a co-design system, including a co-draw component and a co-editor com-ponent, a document transfer system and a multimedia e-mail system. The system is based on TCP and UDP protocols and is developed on the SUN SPARC OPENLOOK system. This system is applicable to a number of environments, e.g., office automation, inter-hospital network service, computer supported collaboration work, distributed software development, group decision support, and so on.