In data entry system, it is often needed to communicate with the large computer system by system requirement. Normal data entry operation is performed by the system hardware and software; but it has the limit to process all the requirements of the system such as the amount of data to process and store. Various kinds of terminal emulators can be provided to communicate with other sites. KEYBATCH system is also a kind of such systems. It is configured to process key-to-disk data entry and works with many terminal emulators which can be designed to work in stand-alone mode or to run concurrently with KEYBATCH system operations. 200UT is the batch terminal of CDC. In this thesis, the concurrent KEYBATCH terminal emulator which carries out 200UT line disciplines has been designed to support KEYBATCH system operation whih the concurrent terminal emulator. KEYBATCH modules related to the emulator are modified and the emulator modules including the line control, CRT control and the communication task control modules are disigned to work concurrently with KEYBATCH system.