One of the features of some two-way radio models is the Emergency alert button. When pressed, this button sends out a distress call to other radios within range. This feature allows the user to quickly send out a distress signal in case of an accident or other emergency. Also, emergency alert calls generally have a priority over all other calls.
To activate the Emergency Alert feature, the user holds the button down for a configured number of seconds and a distress tone is sent to all other radios. In some models, the radio also automatically changes to the hands-free mode to enable the user to transmit a voice message to the receiving radios.
One model with this feature is the MURS 110 Commercial Handheld Two-Way Radio.