Greg Toppo

USATODAY

Family members of a few passengers aboard missing Malaysia Airlines Flight MH370 are pushing the airline to search for the GPS location of their loved ones' cellphones after saying they'd successfully placed calls to missing passengers' mobile phones.

But industry experts say ringing phones don't necessarily mean that the calls are going through.

"The ringing is not actually ringing at the other phone yet," industry analyst Jeff Kagan said. "It's just telling you that the network is in the process of finding and connecting to it."

Locally placed calls may connect almost instantaneously, he said, but long-distance or international calls may "ring" several times before the phone is found or the system can't find it and disconnects the call.

Each carrier handles voicemail differently, but in general calls are all handled similarly. The ringing keeps callers from hanging up when they hear no sound, said Amy Storey, spokeswoman for CTIA, the Washington, D.C.-based trade group for wireless carriers. "The ringing sound has nothing to do with the actual 'ringing' of the called party's device," she said.

The ringing is "part of the process of wireless" communication, Kagan said. "In this particular case it's painful because it gives people false hope."

During a meeting with passengers' families, Malaysia Airlines' Hugh Dunleavy said the company had similar results — it tried calling mobile phones of crewmembers, which also rang.