I have my Passcode Lock set to 15 minutes with an 8-digit minimum alpha/numeric passcode (corp. policy). If I'm on a call where I don't use my phone (4S with iOS 7) for more than 15 minutes the screen locks and I no longer have my call controls to let me mute/unmute or end the call. So, in order to do any of these basic call functions I have to wake up the phone...swipe...type my 8+-digit passcode...switch to the phone app (if needed)...then hang up, or get off mute. Amy I totally missing something here or did no one at Apple actually try managing a call using iOS 7? BTW, my current workaround is to swipe up to enable airplane mode to kill my calls. Really.