.Net SDKs

using System.Runtime.InteropServices;

public class InteroperableService
{
    [DllImport("ECR.dll", CallingConvention = CallingConvention.Cdecl)]
    public static extern int pack(
        string inputReqData,
        int transactionType,
        string szSignature,
        byte[] szEcrBuffer
    );

    [DllImport("ECR.dll", CallingConvention = CallingConvention.Cdecl)]
    public static extern int parse(
        byte[] respData,
        byte[] szRespFields
    );
}

var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.Connect("192.168.0.102", 8888);

byte[] buffer = new byte[4096];
InteroperableService.pack(requestData, 0, signature, buffer);
socket.Send(buffer);

byte[] response = new byte[4096];
socket.Receive(response);

byte[] fields = new byte[8192];
InteroperableService.parse(response, fields);
string result = Encoding.UTF8.GetString(fields);