47 CFR 10.530: Common vibration cadence.

A Participating CMS Provider and equipment manufacturers may only market a mobile device for public use under part 10 as a “WEA-capable mobile device” if the mobile device includes a vibration cadence capability that meets the requirements of this section.

(a) The vibration cadence must have a temporal pattern of one long vibration of two (2) seconds, followed by two short vibrations of one (1) second each, with a half (0.5) second interval between each vibration. The entire sequence must be repeated twice with a half (0.5) second interval between each repetition.

(b) The vibration cadence must be restricted to use for Alert Messages under part 10.

(c) A device may include the capability to mute the vibration cadence.