Berlin, Germany – Invoking Cortana on Windows Phone is a straightforward affair with a single button press of the Search key (or swipe-down on the HTC One for Windows with Dot View case). However, newer technology found on the Xbox Kinect and some other Android devices is making the jump to Windows Phone: passive voice activation.

Arriving later this fall with the newly announced 'Lumia Denim' firmware update, some Lumias are getting the hands-free feature named 'Hey Cortana.' Users with smartphones featuring the Snapdragon 80x chipsets, like the Lumia 930, Lumia Icon, and Lumia 1520 can all take advantage of the Cortana extension.

After a brief training session whereby the phone learns your specific voice, users will be able to call up Cortana by simply saying 'Hey, Cortana' (or any other name they bequeath to the voice-assistant). Cortana then wakes up and takes your inquiry. Such a feature allows users to use Cortana without ever touching their phone, which is perfect if you are across the room, have your hands full, are driving or other situations where it is more convenient to go hands-free.

Presumably other phones like HTC's new One M8 for Windows Phone can do the same, as that phone has the necessary hardware, but it also needs a firmware/OS update to enable the new feature. For Microsoft and their Lumia line, 'Hey Cortana' is supposed to launch with the new Lumia Denim firmware and OS update expected later this fall.

Hints of passive-voice activation for Cortana being enabled came earlier this summer from Microsoft's Marcus Ash who oversees development of the voice-assistant.