signal detecting circuit ds when a source pulse is supplied and q output is at l level and q is at h level dr1 is a rise detecting circuit and if any one of the switches sw1 and sw4 is pushed and a corresponding pulse from the power source is supplied via resistors r1 r4 inverters inv1 to inv4 or gate or1 and dr1 to the input terminal t of the t type flip flop tff and the output of tff is inverted the output signal of or gate or3 is a drive signal to operate the calculator acc and drive the machine motor m the drive signal is output by or gate or3 when any one of the switches sw1 to sw4 is pushed and when the output q of tff is h an output signal of and gate and9 is a stop signal to stop the calculator acc and the machine motor m the stop signal is issued when q output of tff is h and when the switch 3 is not pushed and no pulse is applied to or gate or1 and inverter inv6 and gates and1 to and7 and flip flops ff1 to ff7 are means which discriminate which component part of switch 3 has been pushed and gate and8 and flip flop ffo are means for disciminating and storing signals generated when more than one of the.