How to enable Power key to end calls in Jelly bean 4.1 based Samsung Smartphones?
STEP 1. GETTING STARTED
a). Tap on Phone as shown below.
b). Now, Tap on Menu as shown in the image below.
c). A Pop up window will appear, Tap on Call Settings.
STEP 2. ENABLING POWER KEY
d). Under Call Settings, Tap on Call answering/ending option as shown below.
e). Under Call answering/ending, Tap on The power key ends calls.
Observe that The Power key ends calls has been enabled.