Bluetooth versions and their differences

  Bluetooth technology is designed to transmit data at small distances in the ISM band. Normally it is no more than 100m for the latest versions.

The speed of Bluetooth is significantly lower than Wi-Fi, but at the same time it consumes less battery power and allows devices to connect to each other faster. In addition, Bluetooth connections are resistant to various kinds of broadband interference, and the equipment for their implementation is very inexpensive.

    Version 1.0

It was published in 1998. and allowed to transmit data at a distance of several meters. It had poor compatibility between products from different manufacturers and  there was no secure connections at the protocol level. This version has not been used for a long time.

    Versions 1.1 and 1.2

These updates include support for unencrypted channels, displaying the power of the incoming signal, and accelerated the process of detecting / connecting devices. The noise immunity was also increased, the broadcast speed (721Kbit / s) was increased, and network anonymity was implemented. These versions made it possible to transmit voice messages and stereo sound (A2DP profile). Currently, you can buy a cheap phone from a Chinese manufacturer with update 1.2.

    Version 2.0 and 2.1

Update 2.0 was released in 2004, 2.1 - in 2007. It had much better energy efficiency. The main feature of Bluetooth 2.0 is the introduction of EDR technology, which increased the speed to 3Mbit / s (in reality, it  was often less then 1.5-2Mbit / s). Today you can buy an inexpensive smartphone that supports this technology.
Version 2.1 is the most popular Bluetooth update. It is compatible with virtually all devices on the mobile market. Moreover, if smartphones / tablets use Bluetooth of more recent updates, then in wireless mice, keyboards, headsets, etc. quite often the standard 2.1 + EDR is implemented. These updates include support for unencrypted channels, displaying the power of the incoming signal, and accelerated the process of detecting / connecting devices. The noise immunity was also increased, the broadcast speed (721Kbit / s) was increased, and network anonymity was implemented. These versions made it possible to transmit voice messages and stereo sound (A2DP profile).

Power consumption in version 2.1 decreased by almost 10 times, an additional bandwidth appeared, which facilitated the use of several connections simultaneously. Implemented a one-touch connection.

    Version 3.0

It was released in 2009 and for the first time used high-speed (HS) data translation. Speed ​​increased to 24 Mbps. This was realized through the installation of two modules (Bluetooth2.1 + EDR and a module that operates on the 802.11 protocol, as well as Wi-Fi). It is the second module that “gives out” a speed jump, but does not give Wi-Fi compatibility. Small files are transferred using the 2.1 + EDR module, and large files are transmitted using the 802.11 protocol.
The disadvantage of this solution was the increased power consumption.

    Version 4.0 and 4.1

Wi-fi.jpg Update 4.0 was released in 2010. It fixed the main disadvantage of HS - excessive energy consumption. Specification 4.0 included a “traditional” Bluetooth module and high-speed transmission (based on Wi-Fi). A Bluetooth protocol with minimal power consumption has also been added. They are mainly used in electronic sensors, mini-sensors (including medical ones), etc.
Connection establishment time decreased to 5ms, transmission distance increased to 100m. AES encryption has been introduced to protect data. This version is implemented in fresh models of major manufacturers and is installed on the flagship smartphones Hayskrin.
Update 4.1 introduced in 2013. The main improvements relate to the joint functioning of Bluetooth and the LTE standard. Data packets are automatically coordinated for mutual protection.
When choosing a smartphone, do not confuse Bluetooth versions and profiles. A profile is a set of functionalities; different versions can implement the same profile. For example, speech and stereo sound are transmitted starting from update 1.2. In this case, for each specific device, only a certain functional set may be available, smaller than that incorporated in the used version of Bluetooth. Thus, for the successful interaction of Bluetooth devices, they must have support for the same profile (Bluetooth versions may be different).

    Versions 4.0, 4.2 and 5.0

In 2018-2019, the most common versions are Bluetooth 4.0 - 4.2 and 5.0. At the same time, the Bluetooth 4.2 standard is announced as a version with improved parameters, providing new solutions for the "smart home", new profiles, like IPSP. Version 5.0 is proposed as a new standard with a higher data transfer rate, which developers will mostly appreciate and improved capabilities for wireless technologies