Abstract: A remote-control system is used in combination with a sewing machine for controlling revolution of a sewing machine motor. A remote-controller is connected to a main body of the sewing machine and operated by the sewing machine operator to change a resistance value of a variable resistor contained therein so that the sewing machine motor is driven under control in response to an output volume from the variable resistor. A condensor is connected to said variable resistor and chargeable by a power supply source mounted in the sewing machine main body. The output voltage is converted into a corresponding digital value at each timing when the condensor is saturated with electricity in response to a clock pulse signal at a predetermined interval. The output voltage at such timing will be in proportion to the resistance value of the variable resistor which is, in turn, in porportion to the amount of operation of the remote-controller.

Abstract: A process for stitching a buttonhole in the forward and reverse fabric feeding directions by means of a zigzag sewing machine including the step of producing one or more of stitches at a critical pattern changing point which will serve as a reference mark for enabling the sewing machine operator to operate the sewing machine as required with ease for the pattern changing operation.