Touchatag RFID Reader - ArchWiki

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Touchatag is a RFID tag reader from Touchatag. It is a cheap set consisting of an ACR122U USB tag reader and MiFare Ultralight RFID tags (USB ID `072f:2200`, use `lsusb -v` to check the firmware version − 2.14 as of 2020-05-10 − under the `bcdDevice` descriptor).

Note: Always put a tag on the reader, otherwise you might encounter problems.

## Installation

Stop the conflicting drivers (`nfc`, `pn533` and `pn533_usb`) from loading.

See the note about blacklisting drivers: the can still be loaded manually, so you should create the following file:

    /etc/modprobe.d/blacklist.conf

    install nfc /bin/false
    install pn533 /bin/false
    install pn533_usb /bin/false

Reload udev rules, unload the conflicting modules if they were loaded already:

    # rmmod pn533_usb pn533 nfc

or simply reboot.

There are two options for connecting the tag reader to libnfc. Difference between them is detailed on stackoverflow.

### USB

This is the modern and recommended way to use this device.

To use `acr122_usb`, you do not need to run the pcsc daemon (libnfc README currently tells you to run it, but this is for the PC/SC way).

Install libnfc.

### PC/SC

This is the legacy and deprecated way to use this device.

Install ccid and pcsc-tools.

## Usage

### USB

Check if the device is detected:

    # nfc-list

    nfc-list uses libnfc 1.7.1
    NFC device: ACS / ACR122U PICC Interface opened

Reading NFC cards works as well:

    # nfc-poll

    nfc-poll uses libnfc 1.7.1
    NFC reader: ACS / ACR122U PICC Interface opened
    NFC device will poll during 30000 ms (20 pollings of 300 ms for 5 modulations)
    ISO/IEC 14443A (106 kbps) target:
        ATQA (SENS_RES): 00  04
           UID (NFCID1): 42  14  3e  2e
          SAK (SEL_RES): 08
    Waiting for card removing...nfc_initiator_target_is_present: Target Released
    done.

### PC/SC

To test the device run:

    # pcscd -f

Start `pcscd.service`, then put a tag on the reader, the result should look like the following:

    # pcsc_scan

    PC/SC device scanner
    V 1.4.17 (c) 2001-2009, Ludovic Rousseau <ludovic.rousseau@free.fr>
    Compiled with PC/SC lite version: 1.6.6
    Scanning present readers...
    0: ACS ACR122U 00 00

    Mon Mar 21 18:16:07 2011
     Reader 0: ACS ACR122U 00 00
      Card state: Card inserted, Shared Mode,
      ATR: 3B BE 95 00 00 41 03 00 00 00 00 00 00 00 00 00 02 90 00

    ATR: 3B BE 95 00 00 41 03 00 00 00 00 00 00 00 00 00 02 90 00
    + TS = 3B --> Direct Convention
    + T0 = BE, Y(1): 1011, K: 14 (historical bytes)
      TA(1) = 95 --> Fi=512, Di=16, 32 cycles/ETU
        125000 bits/s at 4 MHz, fMax for Fi = 5 MHz => 156250 bits/s
      TB(1) = 00 --> VPP is not electrically connected
      TD(1) = 00 --> Y(i+1) = 0000, Protocol T = 0
    -----
    + Historical bytes: 41 03 00 00 00 00 00 00 00 00 00 02 90 00
      Category indicator byte: 41 (proprietary format)

    Possibly identified card (using /usr/share/pcsc/smartcard_list.txt):
    3B BE 95 00 00 41 03 00 00 00 00 00 00 00 00 00 02 90 00
            touchatag SAM card

## Tips and tricks

### tagEventor

tagEventor runs in the background and executes scripts when a tag enters or leaves your tag reader.

Download a binary version or compile your own.

Run tagEventor to test your installation:

    # tagEventor -v 1

The scripts are located in `/etc/gtagEventor`. Read the tagEventor documentation on how to use them.

## Troubleshooting

### Firmware […] is bogus! Upgrade the reader firmware

If you encounter a problem like this:

    ccid_usb.c:859:ccid_check_firmware() Firmware (1.00) is bogus! Upgrade the reader firmware or get a new reader.
    ifdhandler.c:104:IFDHCreateChannelByName() failed
    readerfactory.c:1050:RFInitializeReader() Open Port 200000 Failed (usb:072f/2200:libusb:006)
    readerfactory.c:233:RFAddReader() ACS ACR122U PICC Interface init failed.

The libnfc README suggests to do the following:

Removing the bogus firmware detection of libccid: edit `libccid_Info.plist` configuration file (usually `/etc/libccid_Info.plist`) and locate `<key>ifdDriverOptions</key>`, turn `<string>0x0000</string>` into `0x0004` to allow bogus devices and restart `pcscd.service`.

Note: If you use ACS CCID drivers (acsccid), configuration file is located in something like: `/usr/lib/pcsc/drivers/ifd-acsccid.bundle/Contents/Info.plist` or `/usr/lib/pcsc/drivers/ifd-ccid.bundle/Contents/Info.plist`.
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- Hardware