In the method of inputting information in an electrical unit, after input of an alphabetic character the character itself, or, for the case in which one or more characters have been input prior to the input of the alphabetic character, the character string formed by the first to the last input character is compared with information entries in a comparison set of information, and, when the input character is the same as the first character of one of the information entries in the comparison set or when the character string agrees with the beginning of one of the information entries in the comparison set, this information entry is offered for input to the electrical unit. The information entry offered for input is preferably displayed with all its characters on a display device prior to input. The offered information entry can then be rejected by the operator of the electrical unit by inputting another alphabetic character immediately following input of the alphabetic character. Alternatively, the offered information entry can be input by the operator.