In recent TWS something to shift the ear, to see some of the source code, find a new concept, IBRT not clear, hold happiness and earth attitude, I looked in detail some of the code, check some information, or not found little information of value. At least, I suddenly felt some what understand. Here quickly write it down. Before I forget.
When a device enters the state found another device called: inquiry in this sub-state: it will repeat the page is sent packets in different frequency hopping. A device wants to be found, they must periodically enter the inquiry scan to respond to inquiry messages, where the inquiry response pin is optional.
Bluetooth address and clock information in the sub-state inquiry, inquiry Response frame is found the device device contains, in addition, discovered devices sometimes extended inquiry response packet transmission frame, where it will generally comprise local the name of the device information and support. The cross is the following inquiry message:
The general inquiry broadcast frame does not contain information of the source device. However, it will mark what kind of equipment will send response frame, where the general inquiry access code (GIAC) indicates that any device will return value. Here's dedicated inquiry access codes (DIAC) that only a specific device will have to respond. inquiry access codes are available from the Bluetooth address of the reserved addresses inside. Here is a look at how this is included in the Bluetooth address inside.
Bluetooth address consists of two parts, a high 24bit company id, low internal 24bit is assigned, wherein 0X9E8B00 ~ 0X9E8B3F is reserved, 0X9E8B33 is a general inquiry access code, 0X9E8B00 is Limited Dedicated inquiry access code.
In order to more clearly see out on the air interface package of inquiry access code is indeed 0x9E8B33:
Access code just spent a great effort to explain the above inquiry, it is to let everyone see clearly now IBRT principle TWS headset. In fact, IBRT DIAC is to rely on to make a connection between the two headphones, so you are not understand something. A lot of things, can not see through that thoroughly, and if we are unable to see through that thoroughly.