definition of iw_quality fields

David Gibson david at
Fri May 28 01:23:58 GMT 2004

On Thu, May 27, 2004 at 05:13:01PM +0200, Cristian Hesselman wrote:
> Hi,
> I'm using the orinoco_cs driver and I'd like to make signal strength
> measurements. However, the definition of qual, level, and noise (struct
> iw_quality) is unclear to me. What do they mean? Specifically:
> - Does the orinoco_cs driver report signal and noise strenghts in dBm or
> in some other unit? I checked the code of the mwavelan_cs driver, and it
> translates whatever comes out of the hardware into dBm. However, I
> didn't find such a translation in the orinoco_cs code.
> - Is the qual field an RSSI?
> - Why am I seeing quality values such as 224/92 in iwlist's output when
> 92 is supposed to be the 'quality' maximum?

Unfortunately I've never had adequate information on the meaning of
the figures returned by the firmware for signal quality, so the
driver's interpreatation of them is probably wrong.  Worse, I'm not
sure the figures have identical meanings across all firmware variants.

David Gibson			| For every complex problem there is a
david AT	| solution which is simple, neat and
				| wrong.

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