KVM switches can have a lot of options for you to work with in terms of how you actually make the box switch. Usually there are buttons right on the front of the KVM switch, but other switches give you options of switching by means of hotkeys on the keyboard, mouse clicks, and serial signals to switch.
The hotkeys allow you to enter keystrokes followed by certain commands that will make the switch do various things, such as switch ports. This can make alot of situations alot easier if your keyboard and mouse are fairly far away from your switch, or if pressing buttons on the switch is not convienent for you.
Mouse switching also can help you achieve the same results by clicking the third button on the mouse (usually the middle button.) This can give people the same ease of use as hotkey switching, allowing you to be remote from your KVM switch and still access the server you need to access.
Another convienent but sometimes rare option on a switch is to switch it with RS232 serial commands. This would allow you to use a crestron machine or any type of machine that can output serial signals and use those signals to make your KVM switch change ports. This allows customization of applications and can be very versatile if you are looking for unorthodox methods of switching.
Knowing your KVM switches functionality and asking the right questions can make sure that you have these features and they are working for your benefit.