RFID

RFID readers

pcscd

Is the Linux daemon to access readers compatible with the PC/SC standard.
To dump the readers list supported by libccid of your pcscd install:

 cat /etc/libccid_Info.plist|gawk '
    /ifdVendorID/{
        mode=1
    }
    /ifdProductID/{
        mode=2
    }
    /ifdFriendlyName/{
        mode=3
    }
    {
        inarray=0
    }
    /<array>/{
        i=0
    }
    /<array>/,/<\/array>/{
        inarray=1
    }
    /string/&&inarray{
        match($0,/<string>(.*)<\/string>/,a);
        t[mode i]=a[1]; 
        i++
    }
    END{
        for (j=0;j<i;j++) 
            print t[1 j]":"t[2 j], t[3 j]
    }'

Parallax

http://www.makezine.com/06/theorypractice/ => See MAKE n6

OpenPCD

ACR122U

Intro

based on PN532

docs
- ISO/IEC18092 (NFC) compliant
- NFC Tags Access Speed = 212 kbps
- Support FeliCa card
- Support ISO 14443 Type A & B cards
- MIFARE® cards (Classics, DESFire)
- SAM Socket (optional)

To get the Firmware version string in command line: (actual string here is "ACR122U203" as the last 2 bytes are not SW1/SW2 but part of the string)

$ opensc-tool -s FF00480000
Sending: FF 00 48 00 00.
Received (SW1=0x30, SW2=0x33):
41 43 52 31 32 32 55 32 ACR122U2

You can also use scriptor:

$ echo ff00480000|scriptor           
No reader given: using ACS ACR122U PICC Interface 00 00
Using T=1 protocol
Reading commands from STDIN
> ff 00 48 00 00 
< 41 43 52 31 32 32 55 32 30 33 : Error not defined by ISO 7816

If you get the following error:

Can't allocate Chipcard::PCSC::Card object: No smartcard inserted.

that's because you've a model without SAM support. Place a tag on the reader and try again, it should work.

So that's where a lot of confusion comes into play: the two models behave very differently! see below

ACR122U-SAM

With SAM slot
Windows drivers & API docs

Usage:

When there is a SAM inserted, ATR shown is the ATR of the SAM
When there is no SAM inserted, ATR shown is a pseudo-ATR = 3B 00
So for PCSC there is always a "card inserted"
APDUs are sent to SAM
To send APDUs to a contactless card, you must wrap them into pseudo-APDUs (FF 00 00 00 ...)
To send special APDUs to the reader (to get fw or to control LEDs), just send them

Some more infos here about the Tikitag

ACR122U PICC

Without SAM slot
Windows drivers & API docs

Usage:

When there is a contactless card, ATR shown is the ATR of the card
When there is no contactless card, no ATR
So for PCSC there is a "card inserted" if there is a contactless card
APDUs are sent directly to the contactless card, which makes this reader fully transparent in this mode
To send APDUs to a contactless card, you can also wrap them into pseudo-APDUs (FF 00 00 00 ...)
To send special APDUs to the reader (to get fw or to control LEDs)
- If there is a contactless card, just send the APDUs
- If there is no contactless card, the CCID Escape command must be used (*)

(*) Here is one small example how to use the Escape command:

#!/usr/bin/python
from smartcard.scard import *
hresult, hcontext = SCardEstablishContext( SCARD_SCOPE_USER )
hresult, hcard, dwActiveProtocol = SCardConnect(
hcontext, 'ACS ACR122U PICC Interface 00 00', SCARD_SHARE_DIRECT, SCARD_PROTOCOL_T0 )
IOCTL_SMARTCARD_VENDOR_IFD_EXCHANGE = SCARD_CTL_CODE(1)
CMD = [0xFF, 0x00, 0x48, 0x00, 0x00]
hresult, response = SCardControl( hcard, IOCTL_SMARTCARD_VENDOR_IFD_EXCHANGE, CMD )
if hresult!=SCARD_S_SUCCESS:
     raise error, 'Failed to control: ' + SCardGetErrorMessage(hresult)
print ''.join([chr(i) for i in response])

This requires also to allow libccid to use the Escape command, you've to set bit 0 of ifdDriverOptions in /etc/libccid_Info.plist to 1:

       <key>ifdDriverOptions</key>
       <string>0x0001</string>