1. Turn on the Bluetooth function of the mobile device? (? Is the Bluetooth function of this car turned on by default? )。
2. Search for car Bluetooth with a mobile device, and the name of the car Bluetooth device will be displayed in the mobile device Bluetooth pairing list? ; ? You can also use your own Bluetooth to search for mobile devices, and the names of the searched mobile devices will be displayed in your own Bluetooth pairing list.
3. After the search is successful, touch the Bluetooth name of the vehicle and enter the Bluetooth pairing password according to the prompt of the mobile device. The default is "0000" to pair with the Bluetooth of the vehicle.
4. After successful pairing, the paired Bluetooth model name will be displayed on the car screen. ?
point out
① Operating range between this vehicle and mobile equipment: less than? 5? rice.
② Before connecting the mobile device to this car, you need to be familiar with the Bluetooth function of the device. This car is not guaranteed to be compatible with all mobile devices.
③ Any obstacle between the vehicle and the mobile equipment will narrow the operating range.
Specific introduction:
I. Introduction to Bluetooth
Bluetooth is a wireless technical standard, which can realize short-distance data exchange between fixed equipment, mobile equipment and personal area network of buildings (using UHF radio waves in ISM band of 2.4 ~ 2.485 GHz). 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 Special Interest Group (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. IEEE lists Bluetooth technology as IEEE 802. 15. 1, but this standard is no longer maintained. 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.
Second,? Pairing and connection
1 motivation
More services that Bluetooth can provide may display personal data or be controlled by connected devices. For security reasons, it is necessary to identify specific devices to ensure that you can control which devices can be connected to Bluetooth devices. At the same time, Bluetooth devices need to establish a connection without user intervention (for example, when entering the connection range).
Without solving this contradiction, Bluetooth can use a process called binding. The combination is produced by peeling. The pairing process generates a binding or trigger by a user's specific request (for example, the user explicitly requests to "add a Bluetooth device"), or automatically triggers when connecting to a service that needs to provide a device ID for security reasons. These two cases are called private binding and universal binding respectively.
Pairing usually involves some user interaction, and the device ID has been confirmed. After successful pairing, a binding will be formed between the two devices, and there is no need to repeat the pairing process to confirm the device ID when connecting again in the future. Users can also disconnect as needed.
2 implementation
During the pairing process, two devices can establish a relationship by creating a * * * shared key called a link word. If two devices have the same link word, they can be paired or bound. A device that only wants to communicate with a bound device can use a password to verify the identity of another device to ensure that it is a previously paired device. Once the link word is generated, the authenticated asynchronous connectionless (ACL) link between two devices can be encrypted to prevent the exchanged data from being stolen. Users can delete the link words on any device, that is, unbind two devices, that is, one device may have a link word that is no longer paired with it.
Bluetooth service usually needs encryption or authentication, so it needs pairing before allowing devices to connect remotely. Some services, such as object push mode, do not explicitly require authentication or encryption, so pairing will not affect the user experience related to service use cases.
3 pairing mechanism
After Bluetooth version 2. 1 introduced secure simple pairing, the pairing mechanism has changed greatly. The following is a brief summary of the pairing mechanism:
SSP is considered simple for the following reasons:
4 security issues
Before Bluetooth 2. 1, encryption is not required, and it can be turned off at any time. And the valid time limit of the key is only about 23.5 hours. If the use of a single key exceeds this time limit, a simple XOR attack may steal the key.
Bluetooth version 2. 1 is explained from several aspects:
Link words can be stored in the device file system, not in the Bluetooth chip itself. Many Bluetooth chip manufacturers store link words in devices-however, if the device is mobile, this means that the link words may also move with the device.
Third, interference.
USB3.0 devices, ports and cables have been proved to interfere with Bluetooth devices, mainly because their electronic noise is in the same working frequency band as Bluetooth. Due to the close distance between Bluetooth device and USB 3.0 device, the throughput will decrease or the connection between Bluetooth device and computer will be completely disconnected.
There are many strategies to solve this problem, including increasing the distance between USB3.0 devices and other Bluetooth devices, or buying simple solutions such as USB cable with better shielding performance. Other solutions include extra shielding of Bluetooth originals in the computer.