A soft key is an unlabelled or generically labelled hardware button located right at the edge of a screen. The equipment's software displays a dynamic label on the screen directly adjacent to the button, indicating what it does in the active menu context. This design allows complex test equipment like oscilloscopes and spectrum analyzers to offer deep menu systems without requiring a massive physical keyboard.
Heard on the job
Hit the third soft key on the right to switch the trigger mode from auto to normal.
Insider tip
On bench test equipment, soft keys are preferred over pure touch screens because they provide tactile feedback and work reliably when the operator is wearing gloves.