PURPOSE: To realize the emulator which simulates the mode of the display picture of a handy terminal on a developing machine.

CONSTITUTION: A set file where the initialization condition of the handy terminal is preliminarily prepared. An emulator EM consisting of function routines defined with the same argument as a program for the handy terminal reads 10 the set file at the time of starting and emulates respective functions constituting the hardware constitution on the developing machine side in accordance with specifications of the handy terminal on the entered condition of the set file.