USB Bluetooth 4.0 dongle data transfer speed - Page 1
Forum section: electronics / general

author: Srbel
author_rank: Frequent Contributor
timestamp: November 12, 2016, 01:29:12 pm
content: So, I bought a new phone that has Bluetooth 4.0. And I have an old laptop that has a slow Bluetooth (don't know what version, probably 1 or something). So I thought, time to upgrade with an external (USB) Bluetooth dongle. So I look at USB Bluetooth 4.0 dongle, and what they say that maximum data transfer speed is? Up to 3 Mbps. -.- Are they serious? Why is that slow?

author: andtfoot
author_rank: Unknown
timestamp: November 12, 2016, 01:35:03 pm
content: The limitation appears to be the Bluetooth itself.According to the wikipedia article (https://en.wikipedia.org/wiki/Bluetooth#Uses), the transfer rate for Bluetooth 4 is 25Mbit/s, which is ~3.125MB/s. Is it possible the dongle is 3MBps (not 3Mbps)?

author: Srbel
author_rank: Frequent Contributor
timestamp: November 12, 2016, 01:42:46 pm
content: It says 3Mbps.https://www.asus.com/Networking/USBBT400/specifications/

author: Monkeh
author_rank: Super Contributor
timestamp: November 12, 2016, 02:27:25 pm
content: A: Bluetooth is slowB: That thing has no antenna to speak of

author: andtfoot
author_rank: Unknown
timestamp: November 12, 2016, 02:51:50 pm
content: Quote from: Srbel on November 12, 2016, 01:42:46 pmAh, fair enough.Looking around, it appears to be a pretty common spec; not sure why.

author: Ampera
author_rank: Super Contributor
timestamp: November 12, 2016, 03:27:23 pm
content: But as a question, what does this have to do with a possible USB 4.0?

author: SeanB
author_rank: Super Contributor
timestamp: November 12, 2016, 03:48:56 pm
content: Quote from: TwoOfFive on November 12, 2016, 03:27:23 pmFixed the heading for you......Not USB but bluetooth.

author: jazz
author_rank: Contributor
timestamp: November 12, 2016, 04:12:03 pm
content: I suspect it's similar to the reason why devices list USB 2.0 support even though they only support the slow full speed USB mode (as intruduced with USB 1.0).In the case of USB, devices only supporting the "old" transfer modes have also been included in the newer standard, and similar things may be going on with the bluetooth standard.

author: Srbel
author_rank: Frequent Contributor
timestamp: November 12, 2016, 04:29:18 pm
content: Quote from: Monkeh on November 12, 2016, 02:27:25 pmWell, it is not a cheap dongle. It costs almost 20 euros.

author: Srbel
author_rank: Frequent Contributor
timestamp: November 12, 2016, 04:31:31 pm
content: Quote from: TwoOfFive on November 12, 2016, 03:27:23 pmOps. Fixed.

author: Halcyon
author_rank: Unknown
timestamp: November 13, 2016, 08:38:26 am
content: Quote from: Srbel on November 12, 2016, 01:29:12 pmBluetooth is designed as a cheap, low-power technology. It's not really designed with bandwidth in mind (although there have been improvements with the latest revisions). I personally consider Bluetooth as more of a "legacy" technology when almost all else fails. It's great for small data over short transmission distances. It's fine for low bandwidth streams (like basic audio) but when you're talking about transferring large files (and file sizes for various media are getting larger) then forget it unless you're willing to wait. You're better off just fetching a USB cable in most cases. It's largely the reason why good quality wireless audio prefers Wi-Fi over Bluetooth (such as Sonos, ChromeCast etc...); Bluetooth is just not capable of handling high(ish) bit rate over reasonable distances.

author: timb
author_rank: Super Contributor
timestamp: November 13, 2016, 08:54:09 am
content: Quote from: andtfoot on November 12, 2016, 01:35:03 pmI think that 24Mbit/s speed is only valid for Bluetooth 3.0 + HS and even then, it's not really fair because the data isn't actually transferred over BT at that speed, it's actually transferred over WiFi!Basically, as part of the BT3.0 spec, they have the ability to operate the BT protocol layer over a different transport layer. So, a +HS device will initially connect over BT and handshake, when data needs to be transferred both BT devices hand the data off to a separate WiFi stacks and perform the transfer.It's lame and not very widely implemented.Basically, BT2.1+EDR is as fast as you're going to get from most devices.Most BT4.0+Low Energy (BTLE) devices are *much* slower than the older BT2.1 spec devices (but they're not supposed to be faster, they're designed for periodic bursts that sip power, not pushing large amounts of data).

author: Bassman59
author_rank: Super Contributor
timestamp: November 15, 2016, 12:20:05 am
content: Quote from: jazz on November 12, 2016, 04:12:03 pmThe USB 2.0 spec doesn't require devices to be High Speed. A USB 2.0 device can run at Full Speed (12 Mb/s) or Low Speed (1.5 Mb/s).