1]1i have a gps device that should send GPRMC Data but it require login packect Review the dataSheet Device DataSheet
i can recieve the login 787811010XXX739050313XXX20200001000E0EAD0D0A
IMEI Sart With XXX
the packet is different from the example Image
i have 2 Questions 1-according to the data recieveid and the example what should i send 2- how to calcaulate the Error Check Thank You
Edit
public static void StartListening()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// The DNS name of the computer
// running the listener is "host.contoso.com".
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPAddress local = IPAddress.Parse("My IP");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 8841);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
// Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
// Console.WriteLine(e.ToString());
}
// Console.WriteLine("\nPress ENTER to continue...");
// Console.Read();
}
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void Send(Socket handler, byte[] data)
{
// Convert the string data to byte data using ASCII encoding.
// byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(data, 0, data.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
// Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
}
catch (Exception e)
{
// Console.WriteLine(e.ToString());
}
}
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
static byte[] Unpack(string data)
{
//return null indicates an error
List<byte> bytes = new List<byte>();
// check start and end bytes
if ((data.Substring(0, 4) != "7878") && (data.Substring(data.Length - 4) != "0D0A"))
{
return null;
}
for (int index = 4; index < data.Length - 4; index += 2)
{
bytes.Add(byte.Parse(data.Substring(index, 2), System.Globalization.NumberStyles.HexNumber));
}
//crc test
byte[] packet = bytes.Take(bytes.Count - 2).ToArray();
byte[] crc = bytes.Skip(bytes.Count - 2).ToArray();
uint CalculatedCRC = crc_bytes(packet);
return packet;
}
public static UInt16 crc_bytes(byte[] data)
{
ushort crc = 0xFFFF;
for (int i = 0; i < data.Length; i++)
{
crc ^= (ushort)(data[i] << 8);
for (int j = 0; j < 8; j++)
{
if ((crc & 0x8000) > 0)
crc = (ushort)((crc << 1) ^ 0x1021);
else
crc <<= 1;
}
}
return crc;
}
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
if (state.buffer[3] == 1)
{
string input = BitConverter.ToString(state.buffer, 0, bytesRead).Replace("-", "");
byte[] bytes = Unpack(input);
byte[] serialNumber = bytes.Skip(bytes.Length - 2).ToArray();
byte[] response = { 0x78, 0x78, 0x05, 0x01, 0x00, 0x00, 0x00, 0x0 };
serialNumber.CopyTo(response, 4);
UInt16 sendCRC = crc_bytes(response.Take(response.Length - 2).ToArray());
response[response.Length - 2] = (byte)((sendCRC >> 8) & 0xFF);
response[response.Length - 1] = (byte)((sendCRC) & 0xFF);
Send(handler, response);
// handler.Send(response);
}
else
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
SaveData(content);
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
// }
}
}
}
Vendor DataSheet
4.6. Error Check A check code may be used by the terminal or the server to distinguish whether the received information is error or not. To prevent errors occur during data transmission, error check is added to against data misoperation, so as to increase the security and efficiency of the system. The check code is generated by the CRC-ITU checking method. The check codes of data in the structure of the protocol, from the Packet Length to the Information Serial Number (including “Packet Length” and “Information Serial Number”) , are values of CRC-ITU. CRC error occur when the received information is calculated, the receiver will ignore and discard the data packet. 4
DataBase Table
CREATE TABLE [dbo].[T_Tracking](
[id] [int] IDENTITY(1,1) NOT NULL,
[IMEI] [nvarchar](50) NULL,
[TrackTime] [datetime] NULL,
[CurrTime] [datetime] NULL CONSTRAINT [DF_T_Tracking_CurrTime] DEFAULT (getutcdate()),
[Longitude] [nvarchar](50) NULL,
[Lattitude] [nvarchar](50) NULL,
[speed] [float] NULL
You Code
switch (protocolNumber)
{
case PROTOCOL_NUMBER.LOGIN_MESSAGE:
serialNumber.CopyTo(loginResponse, 4);
sendCRC = crc_bytes(loginResponse.Skip(2).Take(loginResponse.Length - 6).ToArray());
loginResponse[loginResponse.Length - 4] = (byte)((sendCRC >> 8) & 0xFF);
loginResponse[loginResponse.Length - 3] = (byte)((sendCRC) & 0xFF);
string terminalID = Encoding.ASCII.GetString(receiveMessage.Skip(4).Take(messageLength - 5).ToArray());
Console.WriteLine("Received good login message from Serial Number : '{0}', Terminal ID = '{1}'", "0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"), terminalID);
Console.WriteLine("Send Message : '{0}'", BytesToString(loginResponse));
Send(state.workSocket, loginResponse);
break;
case PROTOCOL_NUMBER.LOCATION_DATA:
year = receiveMessage[4];
month = receiveMessage[5];
day = receiveMessage[6];
hour = receiveMessage[7];
minute = receiveMessage[8];
second = receiveMessage[9];
date = new DateTime(2000 + year, month, day, hour, minute, second);
Console.WriteLine("Received good location message from Serial Number '{0}', Time = '{1}'", "0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"), date.ToLongDateString()); string lng = message.Substring(22, 8);
Int64 lngVal = Convert.ToInt64(lng, 16);
double step3 = (double)lngVal / 30000;
double step4 = (double)((step3 / 60));
//int lngdeg =Convert.ToInt32( step4.ToString().Split('.')[0]);
// double step5 = (double)(step4 * 60) - step3;
string lat = message.Substring(30, 8);
Int64 altVal = Convert.ToInt64(lat, 16);
double Lstep3 = (double)altVal / 30000;
double Lstep4 = (double)((Lstep3) / 60);
// double Lstep5 = (double)(Lstep4 * 60) - Lstep3;
//Console.WriteLine("Date : '{0}',Long : '{1}', Receive Message : '{2}'", dateStr, step4, Lstep4);
string speedstr = message.Substring(38, 2);
int SpeedVal = Convert.ToInt32(speedstr, 16);
SaveData(IMEI , dateStr, step4.ToString(), Lstep4.ToString(), SpeedVal);//Get IMEI From Login Message that is the Problem
break;
Status Message
