The features field is NOT a value from the CCID USB descriptor. It is a field I added to indicate special features of some readers.
| features | # | % |
|---|---|---|
| features PIN Verification | 39 | 15.35 % |
| features PIN Modification | 36 | 14.17 % |
| features contactless | 31 | 12.20 % |
| features ICCD | 25 | 9.84 % |
| features Multi interface reader | 14 | 5.51 % |
| features 2 slots | 11 | 4.33 % |
| features Second interface | 7 | 2.76 % |
| features biometric | 7 | 2.76 % |
| features 3 slots | 3 | 1.18 % |
| features 5 slots | 3 | 1.18 % |
| features ExpressCard | 3 | 1.18 % |
| features firewall | 3 | 1.18 % |
| features 4 slots | 1 | 0.39 % |
| features serial | 1 | 0.39 % |
Some features can be extracted from the USB descriptor like PIN Verification, PIN Modification, ICCD, number of slot. But the other features are added manually.
A majority of readers have no special feature. It is not directly visible from the table above because some readers have 2 or more features at the same time. For example all readers with PIN modification can also do PIN verification. But the reverse is not true. 3 readers can do PIN verification but not PIN modification.
If you want to find readers with a special feature, like contactless, I recommend to sort the reader matrix by 'features' field. It is then easy to find the readers with the feature you are looking for.