var contextFactory = ContextFactory.Instance;
using (var context = contextFactory.Establish(SCardScope.System)) {
   // your code
}

var contextFactory = ContextFactory.Instance;
using (var context = contextFactory.Establish(SCardScope.System)) {
    Console.WriteLine("Currently connected readers: ");
    var readerNames = context.GetReaders();
    foreach (var readerName in readerNames) {
        Console.WriteLine("\t" + readerName);
    }
}

var contextFactory = ContextFactory.Instance;
using (var ctx = contextFactory.Establish(SCardScope.System)) {
    using (var isoReader = new IsoReader(ctx, "ACME Smartcard reader", SCardShareMode.Shared, SCardProtocol.Any, false)) {

        var apdu = new CommandApdu(IsoCase.Case2Short, isoReader.ActiveProtocol) {
            CLA = 0x00, // Class
            Instruction = InstructionCode.GetChallenge,
            P1 = 0x00, // Parameter 1
            P2 = 0x00, // Parameter 2
            Le = 0x08 // Expected length of the returned data
        };

        var response = isoReader.Transmit(apdu);
        Console.WriteLine("SW1 SW2 = {0:X2} {1:X2}", response.SW1, response.SW2);
        // ..
    }
}

using (var ctx = ContextFactory.Instance.Establish(SCardScope.System)) {
    using (var reader = ctx.ConnectReader("OMNIKEY CardMan 5x21 0", SCardShareMode.Shared, SCardProtocol.Any)) {
        var cardAtr = reader.GetAttrib(SCardAttribute.AtrString);
        Console.WriteLine("ATR: {0}", BitConverter.ToString(cardAtr));
        Console.ReadKey();
    }
}

var monitorFactory = MonitorFactory.Instance;
var monitor = monitorFactory.Create(SCardScope.System);

// connect events here..
monitor.StatusChanged += (sender, args) =>
    Console.WriteLine($"New state: {args.NewState}");

monitor.Start("OMNIKEY CardMan 5x21-CL 0");

Console.ReadKey(); // Press any key to exit

monitor.Cancel();
monitor.Dispose();