1. Master and slave of Bluetooth communication
Bluetooth technology stipulates that when each pair of devices performs Bluetooth communication, one must be in the master role and the other in the slave role in order to communicate. During communication, the master must search for and initiate pairing. After the link is established, the two parties will Can send and receive data. In theory, a Bluetooth master device can communicate with 7 Bluetooth slave devices at the same time. A device with Bluetooth communication function can switch between the two roles. It usually works in slave mode and waits for other master devices to connect. When necessary, it switches to master mode and initiates calls to other devices. Bluetooth headset OEM manufacturers believe that when a Bluetooth device initiates a call in the master mode, it needs to know the other party's Bluetooth address, pairing password and other information. After the pairing is completed, the call can be initiated directly.
2. Bluetooth call process
bluetooth headset oem manufacturers believe that when a Bluetooth master device initiates a call, the first step is to find out the Bluetooth devices around which can be found.
After the master device finds the slave Bluetooth device, it will pair with the slave Bluetooth device. At this time, you need to enter the PIN code of the slave device, and some devices do not need to enter the PIN code. After the pairing is completed, the slave Bluetooth device will record the trust information of the master device. At this time, the master can initiate a call to the slave device, and the paired device does not need to be paired again during the next call. The paired device, as the slave Bluetooth headset, can also initiate a link establishment request, but the Bluetooth module for data communication generally does not initiate a call. Bluetooth headset oem manufacturers believe that after the link is successfully established, two-way data or voice communication can be carried out between the master and the slave. In the communication state, both the master and slave devices can initiate link disconnection and disconnect the Bluetooth link.
3. Bluetooth one-to-one serial data transmission application
In Bluetooth data transmission applications, one-to-one serial data communication is one of the most common applications. Bluetooth headset oem manufacturers believe that the pairing information between the two Bluetooth devices is set in advance before the Bluetooth device leaves the factory, and the master device pre-stores the slave device PIN code, address, etc., the device at both ends will automatically establish a link after power on, transparent serial port transmission, without the intervention of peripheral circuits. In one-to-one applications, the slave device can be set to two types. One is the silent state, that is, it can only communicate with the designated master and cannot be searched by other Bluetooth devices; the second is the development state, which can be searched by the designated master. , It can also be searched and established by other Bluetooth devices.