On the new iPhone 6S, it does not need to be plugged in.<p>&gt; The integrated M9 works so eﬃciently and intelligently that Siri is always on and waiting for your voice commands. You can easily activate Siri by saying “Hey Siri” whenever your iPhone 6s is nearby.<p>(Taken from <a href="http:&#x2F;&#x2F;www.apple.com&#x2F;uk&#x2F;iphone-6s&#x2F;technology&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.apple.com&#x2F;uk&#x2F;iphone-6s&#x2F;technology&#x2F;</a>)