PURPOSE: To indicate clearly the number of key-in digits, the format of key-in data, and a key-in group, and also to display exactly setting operation procedures, by displaying a cursor of a color on a key-in display area.

CONSTITUTION: Keys of a keyboard are divided into groups for each function or type, and each group is colored (POINTWgreen, DATAWwhite), or a symbolic mark is put to each group. A selecting range of the keys can be made small by dividing them into each group, therefore, when display of a color (display of symbolic marks such as *, #, etc.) is performed to the key-in part, key-in can be executed by using a key painted with its color. Also, the key-in number is known by the number of display pieces of a color of the key-in part, and the format of data to be keyed-in is also known by combination of colors. That is to say, the key-in number can be indicated exactly by the number of display pieces of each item by a guide display 1, and also a group of a key to be keyed- in can be designated by designating a color.