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Changing the default voltage of my smart card reader

The voltage selection can be tuned using a dedicated registry key. This setting is relevant with the Gemalto official driver only of course.

To change the reader voltage install the latest GemCCID driver version available here (or use Windows Update) and apply the following procedure:

- Open the registry
- Go under the following folder
- Add or modify the VoltageSelection key with appropriate value (ie 0x42 for 3V only).

This Key manages how the Reader will activate the Power on Smart Card. According to the following values, the algorithm will differ.

DWORD Meaning
0x41 5v only
0x42 3v Only
0x43 3v, 5v With Class U verification.
0x44 1.8v Only
0x45 1.8v and 5v With Class U verification
0x46 1.8v and 3v With Class U verification.
0x47 1.8v, 3v and 5v With Class U verification.
0x01 5 v only Without Class U verification
0x02 3v only Without Class U verification
0x03 3v,5v Without Class U verification
0x04 1.8v Without Class U verification
0X05 1.8v, 5v Without Class U verification
0X06 1.8v,5v Without Class U verification
0x07 1.8v, 3v, 5v Without Class U verification

Default: 0x41

Note1 : When Class are combined in VoltageSelection key ( 43,45, ?..), the power applied by the Reader for initiate ATR will be the lowest one.
For example if Key is 0x46, the Reader will apply 1.8v then according to ATR it may change the voltage (see Note below).

Note2: Drivers will apply the highest class returns by SmartCard in its ATR whatever the Key in Registry. For example if Key is 0x43 ( 3v/5v with Class Verification ) and the ATR returns Class A & B, the Vcc apply to Smartcard will be 5v ( Class A).

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