Samsung
Set Side Key to End Calls auf Samsung
By default, the side key on a Samsung phone only locks the screen or triggers whatever shortcut you assigned to it, depending on your setup. Ending an active call with it requires a separate toggle hidden inside the call settings, not the general side key settings.
This toggle is called Press Side key to end calls. It only changes behavior while a call is on screen. Outside of a call, the side key keeps doing whatever it normally does, such as locking the phone or opening the power menu.
To turn it on, go to Tap on Phone ➔ Open the Menu ➔ Tap on Settings ➔ Tap on Answering and ending calls ➔ Enable or disable Press Side key to end calls.
Once enabled, a single press during an active call hangs up right away, no need to touch the display at all. This helps when the screen is hard to reach, for example during a workout or while the phone sits in a car mount.
Other side key shortcuts, like opening the camera or Bixby, are not affected. The end-call behavior only applies while a call is active, so there is no overlap with your usual side key setup.
If accidental presses start cutting calls short, for example when the phone rides in a tight pocket, just disable the same toggle again.