According to the state machine to describe the operation of the link layer
There are five kinds of state:
? The ready state
? State radio
? Scanning state
? A state
? Connection state
Scanning state
Scanning state of link layer will send packets listening radio equipment in the broadcast channel, scanning state of equipment is the scan,
State radio
Radio state of the link layer will be broadcast channel to send packets, listening to and through the radio channel response packet, broadcast condition of equipment is the broadcast,

Example:
After power on the bluetooth module send radio channel radio signal monitoring, and response to a request packet of radio channel, bluetooth module is an advertiser, electrical work on the USB Dongle, users to send after Scanning the AT command, enter the Scanning State, the broadcast packets to start listening to the radio channel, so the USB Dongle is a scanner,

CodePudding user response:

Then you have to ask what problem

CodePudding user response:

CodePudding user response:

Understanding, good dongdong