Many alarm companies use the system to alert police or fire departments to emergencies at homes or businesses. About three years ago, the Alarm Industry Communications Committee (AICC) industry group took a survey which revealed that just under 1 million of the approximately 30 million monitored home and business alarm systems used an analog cellular network, said AICC chairman Louis Fiore. About 850,000 of them used the system only as a backup in case the phone line was cut, he said.
Alarm manufacturers are now replacing many of those analog systems with digital ones, Fiore said. About six months ago, the manufacturers believed there were about 400,000 AMPS systems still in the field, he said.
Some customers of GM's OnStar roadside assistance plan have cars old enough to lose their OnStar service when the analog towers go dark as well. They appear to have working telephones, though; they've called a lawyer and have initiated a class-action lawsuit over it.