Switch voltage (VSW) is the maximum voltage that can be applied at the input pin with respect to ground. Enable/disable time (ten/tdis) is the time it takes for the switch to change state from the time the select pin has been triggered. Select or control pin threshold levels (TTL vs. CMOS) indicate the different threshold levels at which the switches are triggered. As an approximation, TTL threshold levels are at 0.7 and 1.4V. CMOS levels are typically at 30% and 70% of the supply voltage. One has to be careful to select the right switch to guarantee the selected signal used can correctly trigger the switch. Package selection is also important. There are multiple package and pin configurations available. Therefore, ensure select the proper package option is selected to ease the layout of the PCB.