If you are a little bit interested in the technology of  Bluetooth,you may curious about the difference amony Bluetooth adapter 4.0,Bluetooth adapter 3.0 and Bluetooth adapter 2.0.

So let's talk about it at length today.

Bluetooth adapter 2.0: its speed is not so fast, only short-distance file reception and transmission are supported.Pairing between Bluetooth 2.0 devices requires manual password input. 

The most widely used way is the Bluetooth 2.0+EDR standard, which was introduced in 2004, and products that support the Bluetooth 2.0+EDR standard also appeared in 2006.
Although the Bluetooth 2.0+EDR standard has made a lot of technical improvements, the problem of complicated configuration process and high power consumption of the device continues from the 1.X standard.

Bluetooth adapter 3.0：in terms of power consumption, due to the introduction of the Enhanced Power Control (EPC) mechanism, and 802.11 is added. Although more energy is consumed when it transmits data at high speed, the actual idle power consumption is greatly reduced. The problem of standby power consumption of the Bluetooth device is solved.Also,as the Bluetooth standard released in 2009, through the integration of "802.11 PAL" (protocol adaptation layer), the data transfer rate of Bluetooth 3.0  was raised up to 24MBPS, which is 8 times the old standard 2.1 and can easily achieve data transfer of video recorder to HDTV, PC to  PMP,UMPC to  printer;

Bluetooth adapter 4.0: it is faster, and you can connect up to 7 Bluetooth headsets at the same time.Its power consumption is lower.Pairing between Bluetooth 4.0 devices will automatically generate a password, and it just needs to click OK.

Bluetooth 4.0 is the upgrade standard of Bluetooth 3.0. The biggest feature of Bluetooth 4.0 is power saving, which greatly improves the standby time of Bluetooth headset. His extremely low running and standby power consumption can make a standard button battery work for several years.  Moreover, 3 milliseconds low latency, ultra long distance transmission over 100 meters, AES-128 encryption, low cost and high cross-vendor interoperability are also new features of Bluetooth 4.0. Now Bluetooth Headphones,which are available on the market are mostly Bluetooth 3.0, only a small number of Bluetooth headsets are based on the Bluetooth 4.0 standard. Relatively speaking, the price of the Bluetooth headset of the 4.0 version is higher.The cost of development as a new technology and the media hype are the two main factors.

All in all,the higher the version, the less power is consumed, of course, the more specific the function is.