BOS-GSM
BOS-GSM (depending on the provider also BOS @ GSM, GSM-BOS ) is a technology for digital radio communication of users with special security requirements such as authorities and organizations with security tasks (BOS: police , fire brigade , rescue services ).
The planned variant of the public GSM digital radio network was offered by some digital radio network operators as an alternative to the specialized radio networks based on the TETRA and Tetrapol standards . With the help of so-called ASCI features (Advanced Speech Call Items), the public GSM network is expanded to include special security functions, such as the prioritization of calls and functions for closed user groups. Private users of the GSM network would be forced out of the network in an emergency in order to maintain the network's efficiency. Direct communication between end devices without integrating the network infrastructure (DMO, Direct Mode) is implemented using special end devices that can use a separate frequency range (e.g. 380 to 400 MHz). By opting for TETRA, this system did not come into effect.