An all-points bulletin (APB) is an electronic information broadcast sent from one sender to a group of recipients, to rapidly communicate an important message. The technology used to send this broadcast has varied throughout time, and includes teletype, radio, computerized bulletin board systems (CBBS), and the Internet. The earliest known record of the all-points bulletin is when used by United States police, which dates the term to 1947. Although, used in the field of policing at the time, the APB has had usage in fields such as politics, technology and science research. However, since the 21st century, due to advances in technology, all-points bulletins have become significantly less common and are now only primarily used by police departments in countries such as the United States, Canada, Australia and the United Kingdom. Technological functionality Pre-21st century The functionality of all-points bulletins was based on the latest advances in computer networking at the time, developed in the 1940s and continuing evolution through to the 1970s. Different from e-mail or teleconferencing, which are designed for limited list of recipients, all-points bulletins were digital message "broadcast systems". It is described that "each message placed on [an APB] is intended for a wide audience", and they were some of the first technologies which could do so in an efficient and effective manner. Users access these all-points bulletins "through terminals or microcomputers by dialling in over dedicated or general-purpose telecommunication lines". The APB then show messages that will be readable for the users of the system, and in some systems, users are able to attach their own messages similar to a virtual bulletin board. Consequently, messages would not only be able to be seen by the sender, but also by subsequent users of the digital bulletin system, who could also add their own information and messages to this bulletin. Users were thus able to build information upon one another, enabling for discussion of ideas and information between individuals in society from despite using different computers in different locations. However, in regard to the technical functionality of the computerised bulletin systems, there is a lack of significant research on the technical construction and development of these terminals and computers; so modern knowledge of the technicalities of these older all-points bulletin systems is restricted. In the 21st century The modern, 21st Century technological evolution of the all-points bulletin is mainly only used in the world of policing. Police