I have a general question about hardware here, specifically Bluetooth 4.0. I've been looking to upgrade my little Bluetooth USB dongle from an earlier version (I think it's ~2.1) to something newer, but the speeds listed for Bluetooth 4.0 do not make sense on NewEgg / vendor sites.
http://en.wikipedia.org/wiki/Bluetooth
Version Data rate Maximum application throughput
Version 1.2 1 Mbit/s 0.7 Mbit/s
Version 2.0 + EDR 3 Mbit/s 2.1 Mbit/s
Version 3.0 + HS 24 Mbit/s See Version 3.0+HS.
Version 4.0 See Version 4.0LE.
Now, I could be wrong, but I am seeing 4.0 devices listed with 3 MBit/s maximum speeds. Assuming backwards compatibility with previous editions, the maximum speed should be at least 24 Mbit/s.
http://www.newegg.com/Product/Product.aspx?Item=N82E16833320166
Interface
USB 2.0
Bluetooth Standards
Bluetooth 4.0
Transfer rate
Up to 3.0Mbps
I normally enjoy Asus stuff, and have included the above as an example.
Am I just looking at the wrong products? Is there something about the spec I do not understand? Am I reading it incorrectly? Anyone have any idea what's going on here? I don't think it's a limitation of USB 2.0…
Best Answer
The improvements on bluetooth from 2.0 to 4.0 are mainly optional characteristics such as Enhanced Data Rate (EDR) for 2.0 -> High speed (HS) for 3.0 (this takes advantages of lower frequencies like 802.11 and makes the transfer speed go up to 24Mbits/s) -> and finally Low Energy for 4.0 These technologies do not enhance theoretically the transfer speed, and from what information you have given us, I must tell you: you simply swop between Mbytes (with a big B, this means 8bits) and Mbits So when you're saying that 4.0 devices are listed as 3MBits/s, you're confusing yourself, it's 3MBytes/s which means 3*8: 24Mbits/s. There comes the confusion, don't worry, they did not intentionally drop down the transfer speed... Reference/source: see this article and the articles connected https://www.quora.com/What-is-the-difference-between-Bluetooth-4-0-3-0-and-2-0