A telecommunications expert has cast doubt on ambitious plans by security officials to block mobile phone reception but still allow emergency calls during the upcoming APEC Summit in Sydney.
Jeff Kasparian, business manager of the Institute for Telecommunications Research at the University of South Australia, said his group was "not convinced" by counter-terrorism plans to jam mobile phone signals around US president George Bush's motorcade during his APEC visit in September.
The president's motorcade will be shadowed by a helicopter equipped with signal-jamming equipment, blocking mobile reception around it in an area the size of a football field. Terrorists have used mobile phones to detonate remote-controlled bombs in Iraq and in the recent Bali bomb attacks.
The Australian government has assured citizens emergency calls will not be affected by the signal jamming.
However, Kasparian said "highly sophisticated" technology would be needed to block calls in the vicinity of the helicopter but still identify and allow emergency calls.
"We're not convinced you'd be able to do that. There's no distinction between outgoing emergency and normal calls," he told ZDNet Australia.
"I doubt they would have something like that," he said of the required technology. "They would need to have a team with computers on the helicopter."
Calls would most likely be blocked by the helicopter sending out a signal that would "saturate" all mobile devices in the area, according to Kasparian.
He also dispelled the practicality of outgoing calls being allowed, but incoming ones being blocked. This is a possible scenario as incoming and outgoing transmission works on different frequencies.
However, even if security officials only tried to jam incoming calls, there was a "99 percent" likelihood outgoing calls would be affected too, said Kasparian.
"Outgoing calls need dialogue with a base station," he said.
"The problem is if you jam the receiver on the phone the base station can't communicate back to the phone [to set-up the outgoing call].
"Our view is it's highly unlikely you could make an outgoing call."
The level of technology needed to ensure citizens in the affected area could still make calls was probably too great to incorporate into security plans, according to Kasparian.
"I would think it's highly likely that they're just going to disrupt all mobile communications in the area," he said.
Mobile phone jamming is illegal in Australia, although the government has said the security requirements of APEC means some exceptions might be made.
The Australian Mobile Telecommunications Association, Attorney General's Department and the Department of Communications, Information Technology and the Arts all refused to comment for this story.