Journal of Deaf Studies and Deaf Education Vibration Signaling in Mobile Devices for Emergency Alerting: A Study With Deaf Evaluators

Service (CMAS) is being planned to alert cellular mobile device subscribers to emergencies occurring near the loca-tion of the mobile device. The plan specifies a unique audio attention signal as well as a unique vibration attention signal (for mobile devices set to vibrate) to identify that the in-coming message pertains to an emergency. Ratings of vibra-tion signals of varying lengths and patterns were obtained from 44 deaf users of mobile devices for the perceived ef-fectiveness of the signal in getting their attention in an emergency situation. Longer signals received higher ratings than shorter ones, and three signals with temporal on–off patterns were rated significantly better than a constant vi-bration. The U.S. government’s recommended vibration sig-nal for the CMAS, an important feature for access to emergency alerts by deaf persons, is supported by the results of the study. Vibration signals for incoming mobile calls and mes-sages are widely used as an alternative to ringtones in situations where the mobile device user does not wish to disturb others with an audible signal or simply due to personal preference. People who are deaf and many who are hard of hearing depend on vibration signals as the only accessible method of being alerted to calls and messages on a mobile device. A wireless emergency system that does not effectively alert them would put such users in harm’s way, as audio-based sources of immediate information, such as being told by some-one nearby, or a public announcement in a building, would not likely be understood by people who cannot hear well. Thus, vibratory mobile device attention sig-nals are particularly important to this population of people with disabilities. In the United States, a Commercial Mobile Alert Service (CMAS) is being planned as an outcome o