"Reverse 911 calls" — prerecorded robocalls that enable authorities to notify people about imminent dangers such as tornados — don't automatically contact cellular or VoIP phones.
"Landline carriers are required to provide the phone numbers of their customers to local reverse 9-1-1 systems," writes Carmelita Miller on the website of the Greenlining Institute, a think tank in Berkeley, Calif. Cellphone users and VoIP customers generally must sign up to receive emergency alerts.
Harold Feld, senior vice president of Public Knowledge, a consumer watchdog organization in Washington, D.C., says that abandoning a landline to save a few dollars per month can prove costly. "Unlike traditional phones, there's no mandatory quality of service for any of the newer technologies," says Feld. The quality of VoIP and cellphones is "very variable," he says. Medical alert services and remote monitoring of medical devices such as pacemakers that are designed for traditional landlines may or may not "work on an IP substitute and will absolutely not work on wireless," he says.
Feld says landlines could become an endangered species. AT&T and Verizon, the two largest landline providers, are eliminating some landlines because maintaining them is less profitable than providing wireless or VoIP services.
"In a country where we have an increasing number of elderly who need to make sure that medical device and medical alert services work, who need the superior voice quality," says Feld, "how do we make sure they are protected? That's a very big question right now."
David Wallis is a freelance writer for AARP Media.