The MELCOM EX Series was a line of general-purpose computers developed by Mitsubishi Electric. It was designed to be the "core computer of systems" in any application field, and to respond to the ever diversifying and increasingly sophisticated ways of using computers in response to the "advanced information society". A series of models (the EX 830, EX 840, EX 850, EX 860, EX 870 and EX 880) were announced in the period from 1985 to 1987. Later, a new series was developed by improving the compactness and performance of the previous series, and these models (the EX 830 II, EX 840 II, EX 850 II, EX 860 II, EX 870 II and EX 880 II) were announced in the period from 1988 to 1990.
In the MELCOM EX Series,the architecture of hardware, software were evolved, while taking into consideration migration of peripheral devices and software assets which had been used with MELCOM-COSMO Series.