KEYBOARD

PURPOSE:To prevent malfunctions related to the input function of a system by performing the comparison between the operating information on the control key of the keyboard side that can be produced when the buffer of the keyboard is cleared and that of the host computer side. CONSTITUTION:The values obtained in accordance with an operating state indicating whether a key is depressed or released are stored in a buffer 13. Simultaneously, an internal shift flag is sey by an internal shift flag generating means 15. Meanwhile the contents of the buffer 13 are set to an external shift flag by an external shift flag generating means 16 every time the code of a control key is transmitted to the outside from the buffer 13. Then the value of the internal shift flag is compared with that of the external shift flag. When the discordance is detected by comparing the value of the internal shift flag with that of the external shift flage, the information on the control key of the keyboard side is stored in the buffer 13 based on the value of the internal shift flag. Therefore, the control key information on the host computer side is always coincident with that on the keyboard side. Thus, the shift input func tion of an entire system is kept in a normal state.