What are the German BOS?
BOS is a shortcut for "Behoerden und Organisationen mit Sicherheitsaufgaben", what means smth. like "Authorities and organizations responsible for safety/security/rescue".
The most important ones in Germany are the police of the states, the federal police authorities, customs, disaster control, rescue and firefighters.
They all together introduced a common communication standard - this is what these pages are about. Only members of these organisations are allowed to buy, install and use BOS radio units. Each used radio must have a type approval, and each single one has to be registered. This ensures that only radios are used which are totally compatible, and the government has a (limited) control how many radios are in use, and who uses them. Of course sometimes radios get lost or get stolen, also it is possible to program some widespread "normal" radios to act exactly like a genuine BOS approved radio, so it is hard to avoid criminals from having access to one.
Also it has become a quite widespread hobby to listen to the BOS frequencies with VHF/UHF radio scanners. In Germany this is not legal (maybe under some circumstances it can`t be prosecuted), but it is hard to get clear evidence that someone used his scanner to listen to the police - it has become legal to possess a scanner, just its usage in some frequency ranges is not allowed.
To be continued...