Abstract: A time slot-controlling circuit (14, 14'), applicable for use with diverse types of keyboard-operated utilization devices or apparatus (18, 97, 98), such as in a pushbutton telephone (90), allows all (or pre-selected) keyboard-mounted key switches (24a-n, 24a'-h') to acquire a selected one of at least two different time slot-dependent operating states. This advantageously allows each key to initiate or control more than one work (or logic) function performed by an associated keyboard-operated utilization device or apparatus (18, 97, 98), as typically employed in a composite system or apparatus (10, 90). Such a two-state mode of operation is accomplished by each of two illustrative time slot-controlling circuit embodiments (14, 14') comprising a common time slot signal generator (21, 21'), which is responsively connected to a plurality of control signal generating channel selector circuits (22a-n, 22a'-h').