Bluetooth Class ratings

Can anyone tell me what the "Class" rating on BT devices means?
I've seen some vendors list specifications on diffferent models and
some have different class ratings.
What does this signify?
Is one class type better than another?
What should I be looking for or does it matter?
Also, should the BT interface to my PC (the USB key) and my headset
have the same class/be the same class device?

Thanks,
Bruno

Bruno
<email spoofed; just remove the spam in the address>

Bruno wrote:
> Can anyone tell me what the "Class" rating on BT devices means?

The class rating refers to the power class of the radio in the Bluetooth device.

From the Bluetooth specification....

--------------------------------------
| Power class | Maximum Power Output |
|-------------|----------------------|
| | |
| 1 | 100mW (20dBm) |
| | |
| 2 | 2.5mW (4dBm) |
| | |
| 3 | 1 mW (0dBm) |
| | |
--------------------------------------

This also defines the transmission range.

Class 2 devices are by far the most common and have a nominal range of 10M.
Class 1 devices have a longer nominal range of 100M.

Class 3 devices are relatively uncommon and have a range < 10M.
I've never seen a class 3 device marketed.


Obvioulsy you need a pair of class 1 devices to achieve data communication at
~100 Metres.

HTH

Rob

--
Rap it up for the common good
Let us enlist the neighbourhood
It's OK, I've overstood
This is a wordy rappinghood. OK, bye.

Tomtomclub, 1980.

That makes perfect sense.
Thanks for the info!
Bruno

On Fri, 29 Jul 2005 10:07:04 +0100, Rob Shepherd
<robshep@invalid.invalid> wrote:

>Bruno wrote:
>> Can anyone tell me what the "Class" rating on BT devices means?
>
>The class rating refers to the power class of the radio in the Bluetooth device.
>
> From the Bluetooth specification....
>
>--------------------------------------
>| Power class | Maximum Power Output |
>|-------------|----------------------|
>| | |
>| 1 | 100mW (20dBm) |
>| | |
>| 2 | 2.5mW (4dBm) |
>| | |
>| 3 | 1 mW (0dBm) |
>| | |
>--------------------------------------
>
>This also defines the transmission range.
>
>Class 2 devices are by far the most common and have a nominal range of 10M.
>Class 1 devices have a longer nominal range of 100M.
>
>Class 3 devices are relatively uncommon and have a range < 10M.
>I've never seen a class 3 device marketed.
>
>
>Obvioulsy you need a pair of class 1 devices to achieve data communication at
>~100 Metres.
>
>HTH
>
>Rob

Bruno
<email spoofed; just remove the spam in the address>