Card readers that arnt oyster card readers

[Slough]

Please can someone tell me what the yellow card readers are used for at Windsor and eton riverside , datchet and Staines ( okay I know they read cards but what cards ).

I see southern have introduced a key card for certain journeys in the Eastbourne / Brighton area and these seem to use the same reader .

 

[LexyBoy]

They're for SWT's ITSO smartcard scheme, details of which seem to be strangely hard to find on the interwebs. They are the same type as Southern's, but a different technology to Oyster as you say.

 

[Slough]

Thanks