Abstract: The present invention is directed to a system for multiplexing data transmissions exchanged between a host computer system and a user workstation connected by a communications link. One or more host application programs reside upon and are executed by the host computer system while a terminal emulation program having the capability of simultaneously displaying one or more host application program screens resides upon and is executed by the user workstation. The data transmission multiplexing system comprises a session manager program residing upon and executed by the host computer system for establishing one or more program sessions with the host application programs, each of the program sessions generating its own individual datastreams, and a single program session with the terminal emulation program utilizing a single connection between the host computer system and the user workstation.