Secure Means of Communication

In emergency situations which can lead to personal in-juries, communication between people in danger and rescue services is the key to reduce the scope of consequences. Some specific safety systems are designed to allow such communication functions. Numerous technologies are available on the market coming with their ad-vantages and disadvantages with respect to the needs. Some of them are already installed and operated at CERN, such as voice alarm systems, red emergency telephones, TETRA radios, etc. EN-AA group is currently studying various alternatives for upgrading the red emergency telephone system, as well as equipping CERN with a similar option, equally viable, to extend this alert and protection technology to non-radioactive locations on surface and in technical galleries, as required. These alter-natives consist of analogue equipment, TCP/IP, or GSM technology. They will be presented in this paper with brief descriptions for each of them.