Text-based alerts of significant, imminent danger will be able to be sent to most mobile-phone users in a hazardous location in the U.S. beginning Saturday, when the new commercial mobile alert system (CMAS) is scheduled to become operational.

CMAS is a new nationwide alerting system being implemented by the FCC and FEMA in April, in accordance with federal law enacted in 2006. Although the program is voluntary, carriers will have to clearly advertise to potential customers if their networks are not part of CMAS, according to Damian Sazama, vice president of corporate and product marketing for Interop Technologies, which maintains hosted CMAS gateways for Tier 2 and Tier 3 operators.

"These messages are all delivered at no charge to the customer," Sazama said. "The operators are not allowed to charge end users for the delivery of these messages."

CMAS alerts will be delivered via cell broadcast technology, so it should not have the potential delivery bottlenecks associated with normal text messaging solutions during emergencies, Sazama said. On March 28, Interop tested its CMAS gateway with an operator in Puerto Rico.

"Within a minute, once executed by the National Weather Service, a tsunami alert reached the handsets within a few seconds," said Nir Marciano, Interop's product manager. "It was a great success."

Sazama agreed.

"[CMAS] is one of those things that you hope isn't used very often, but when it is, we think it will be a very effective tool," Sazama said.

There are three types of CMAS messages that will exist — presidential alerts, weather alerts and AMBER alerts. All U.S. national carriers have Users are required to receive a presidential alert, which has not been sent since 1951. Users can choose to opt out of AMBER alerts and weather alerts, which are delivered to users that are in locations that are deemed to be dangerous.

"These are just extreme weather alerts," Marciano said. "If there's rain or a thunderstorm in the forecast, you won't receive anything. The alert is for anything that's life threatening — tornadoes, tsunamis, hurricanes or other [potentially] catastrophic storms."