Debian 13: configurating Syris RD200-M1-G v01.55 Card Reader Part 2, detecting card reader in Debian

Add you as group of dialout (20)

# usermod -aG dialout myuser

Note, if you use terminal only, this will effect directly, but if you use window Manager, you require to logout and re-login to make it effect especially on Netbeans, If aftar re-login fail, try restart.  

Confirm which com the reader assign

# ls -l /dev/ttyACM0
crw-rw---- 1 root dialout 166, 0 May 19 13:43 /dev/ttyACM0

The card reader assign com at /dev/ttyACM0

This is simple java code to read card when tap on device

import java.io.FileInputStream;
import java.io.InputStream;

public class TestRD200 {

    public static void main(String[] args) {

        String device = "/dev/ttyACM0";

        try {

            // Configure serial port using stty
            Process process = new ProcessBuilder(
                    "stty",
                    "-F",
                    device,
                    "115200",
                    "cs8",
                    "-cstopb",
                    "-parenb",
                    "raw"
            ).inheritIO().start();

            process.waitFor();

            System.out.println("Listening on " + device);

            InputStream in = new FileInputStream(device);

            byte[] buffer = new byte[1024];

            while (true) {

                int len = in.read(buffer);

                if (len > 0) {

                    System.out.println("READ BYTES: " + len);

                    for (int i = 0; i < len; i++) {
                        System.out.printf("%02X ", buffer[i]);
                    }

                    System.out.println();
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

This is sample output with uid masked

$ java TestRD200
Listening on /dev/ttyACM0
READ BYTES: 8
02 06 xx xx xx xx xx 52 

What they are?

02 STX
06 LENGTH
Data 1-5 xx xx xx xx xx
Checksum 52 

You need to know command in byte, to send to card reader/rfid reader. 

General command format in byte

[stx] [length] [data] [checksum] 

STX
01 Read Card UID
02 Run Action Command
03 Get USB Mode
0C Read user Data
0C Write user Data
0D get S/N
0E Get Model, Version
0F 01 Set Reboot 

e.g. to read Mifare UID (0x11)

command in bytes: 02 01 11 10

02: run command

01: length

11: command to read Mifare UID

10 checksum ( 01 xor 11 )

if return 4 bytes: MIFARE Classic 1K/4K

if return 7 bytes: NTAG / Ultralight / DESFire

if return 8 bytes: ISO15693