Abstract: In this paper a simple, convenient and utility communication software between PC/AT microcomputer and VAX 11/750 computer is provided It can realize local and remote communication and digna(?), duplex transmission between PC/AT and VAX-11/750 without spending any additional hardware cost such as network adapter The system can not only transmit files, but also implement the transmission of record field and even single character. It can also add. delete, correct record fields and save them on disks in the process of transmission. In addition, it gives concrete facilities to match communication rates and to prevent multi-users from conflicting