Bluetooth is a wireless technical standard, which can realize short-distance data exchange between fixed equipment, mobile equipment and personal area network of buildings. Bluetooth technology was first invented by telecom giant Ericsson in 1994 as a substitute for RS232 data line. Bluetooth can connect multiple devices, which overcomes the problem of data synchronization. Today, Bluetooth is managed by the Bluetooth Technology Alliance (SIG). The Bluetooth Technology Alliance has more than 25,000 member companies in the world, which are distributed in many fields such as telecommunications, computers, networks and consumer electronics. Bluetooth Technology Alliance is responsible for supervising the development of Bluetooth profile, managing certification projects and maintaining trademark rights. The manufacturer's equipment must meet the standards of Bluetooth Technology Alliance before it can enter the market in the name of "Bluetooth equipment". Bluetooth technology has a set of patented networks that can be distributed to devices that meet the standards.
? The word "Bluetooth" is the Scandinavian word Bl? tand / Bl？ Tann (that is, old Norwegian blát? Nn), which is the nickname of harald Bluetooth, a king in 10 century. He unified the disputed Danish tribes into a kingdom, and it is said that he also introduced Christianity. The idea of naming Bluetooth after this was first put forward by Jim Kardach in 1997. Kardach has developed a system that allows mobile phones to communicate with computers. He was inspired by the historical novel Long Ships written by Frans G. Bengtsson, which described Viking and Harald Bluetooth King in harald, which means that Bluetooth will also unify the communication protocol into a global standard.
Bluetooth is a packet-based protocol with a master-slave architecture. In the same piconet, the master device can communicate with up to seven slave devices. All devices * * * enjoy the master clock. Packet switching is based on the protocol defined by the master device, and the protocol is 3 12.5? S is the basic clock that runs at regular intervals. Two clock cycles form a 625? S slot, two time gaps form a 1250? The gap of s is right. In the simple case of single slot grouping, the master device sends information in even slots and receives information in odd slots. Slave devices are just the opposite. The packet size can be as long as 1, 3 or 5 slots, but in either case, the master will start transmission from even slots and the slave will start transmission from odd slots.