If you haven't seen it, you should. Here is a description:
"Clay Riddell is a disillusioned artist who a year earlier abandoned his wife Sharon and son Johnny in order to fulfill his dream of publishing a graphic novel. At Boston International Airport, Clay tries to board a flight, hoping to reconcile with his family. His cell phone battery dies, so he calls Sharon using a payphone. Suddenly an electronic signal (later dubbed "the pulse") is broadcast across mobile networks worldwide, turning cell phone users into rabid killers."
Not sure if it's the same one but the movie Telefon (1977) has similar plot.
Yes that's it!