Note that most of the features introduced with newer revisions are optional, and one should pay attention to the added feature, not only the Bluetooth version. The commercial name of this Low Energy (LE) feature is Bluetooth Smart. The main intent of this feature, called Low Energy (LE), is to aggregate data from various sensors, like heart rate monitors, thermometers etc. Bluetooth 4.x - Basic rate + EDR (optional) + HS (optional) + LE (optional) Introduces support for collecting data from very low-rate devices. This optional feature is called High Speed (HS), and, as the name suggests intended to improve speed, with theoretical HS max data rate of 24Mbps when using 802.11 WiFi physical layer. all applications that are available with Bluetooth radio can also be run over an alternate radio ( 802.11). Bluetooth 3.x - Basic rate + EDR (optional) + HS (optional) Introduces support for an alternate lower layer, i.e. SSP is essential for protecting data against man in the middle (MITM) attacks. 2.1 devices feature Secure Simple Pairing (SSP): this not only improves the pairing experience, but increases the use and strength of security. The 2.1 version makes it easier to pair with devices from different manufacturers and increases the reliability of the pairing process. Devices with basic rate + EDR (optional) have theoretical maximum data rate of 3 Mbps. Bluetooth 2.x introduces the optional Enhanced Data Rate (EDR) capability. Those are relic devices that are nearly extinct, useful as collectors items :) Bluetooth 2.x - Basic rate + EDR (optional) The most popular variant, especially 2.1.

In addition to the versions, there are some specific optional features and differences explained in detail below: Bluetooth 1.x - Basic rate bluetooth Bluetooth 1.x has theoretical max data rate of 1Mbps. If given an option, always choose the device with the highest Bluetooth version. In general, each revision of Bluetooth improves upon power consumption, data rate, security, pairing reliability, ease and speed, etc.

Southwing bluetooth 2.0 edr usb adaptor