Abstract: A double action switch, for example having both a rotary action and a pushbutton action, is provided with a removable insert which blocks one action while permitting the other. The switch has a frame in which a shaft is supported, for rotational and axial movements. An insert slides into the frame and engages with the shaft to prevent movement of the shaft for one of the actions, while permitting movement of the shaft for the other action. The switch is particularly useful in a telephone unit in which one or more optional operational features are available. The units can be produced, wired and ready for all options, only those required and paid for being available by use of inserts in the switches.