The Australian Communications Authority has ruled out legalising mobile phone jammers, or making an exception for Australian prisons.

The federal government asked the ACA to investigate the feasibility of allowing States to block mobile phone signals in prisons after State Justice Ministers called for action to prevent incarcerated criminals using mobiles to organise crimes.

ACA chairman, Tony Shaw, said that the ACA understood the concerns raised by Corrective Services and recognised that the use of mobile phones in prisons was a serious problem that needed to be addressed. However, the ACA had found that the disadvantages of allowing the use of mobile phone jammers outweighed the advantages, even in high-risk locations such as prisons.

The reasons given for the 1999 ban on mobile phone jammers haven't changed, according to Shaw.

• Mobile phone jammers cause deliberate interference to licensed services operated by the mobile carriers, and may cause interference to other services operating in adjacent spectrum bands.
• Jammers transmit signals that interfere with reception from mobile phone base stations. All mobile phones being used within a radius of up to four kilometres from the jamming device could be 'jammed'.
• Concern that radiation levels of high-powered devices may result in human exposure to levels of electromagnetic radiation that exceed the maximum permitted under Australian health exposure standards. This has implications for public health and safety, especially in confined areas.

-Jammers cannot be contained to a discrete location and there is a danger of spill-over beyond the area which the device is set up to cover," said Shaw, saying the major issue is that this could affect emergency calls.

-This could create a serious and avoidable risk to life in an emergency by preventing calls being made to 000," said Shaw. -During 2002-03, 29 percent or 1,128,339 of the 3,953,564 genuine calls to the emergency call service originated from mobile phones."

-Because many prisons are close to populated areas, major road and highways, there is a very real risk that legitimate users could be prevented from accessing help in an emergency, with serious consequences," said Shaw.

The ACA Mobile Phone Jammers Report made some recommendations the prisons could use to legally restrict mobile phone use.

These include:

• improved searching at the point of entry to prevent mobile phones or their components being smuggled into prisons, similar to other contraband items; and
• the use of fixed and/or mobile electronic detection devices that can detect when a mobile phone is in operation or in standby mode (and could then be used in conjunction with devices that locate the origin of the signal).

Copyright © 2009 CBS Interactive, a CBS Company. All Rights Reserved.
ZDNET is a registered service mark of CBS Interactive. ZDNET Logo is a service mark of CBS Interactive.