Will switch to voicemail or email if you're close to the speed of light.
NEC will preview the tech next week at MWC and expect it to be commercially available by June 2012.
The solution analyses data to establish, for example, if the user is on a train, at a walking speed or stationary. The software then automatically recommends the most appropriate path for incoming calls, such as a standard ring, voice message or email.
Keiko Matsunaga, VP of NEC Corporation, said: "A person's activity, whether they are driving, in a meeting or exercising, has a significant impact on the best way to take a call.
"NEC's new solution facilitates smoother, less intrusive communications by automatically recommending the most appropriate contact method."