Purpose

The .NET ECR SDK uses P/Invoke to call the native ECR.dll for packing and parsing terminal messages. It provides a standardized API for Windows desktop POS applications, ensuring consistent request/response handling with Nami payment terminals.

Prerequisites

Windows 10 or later
.NET Framework 4.7.2+ or .NET 6+
ECR.dll placed in the application output directory

InteroperableService Class

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
    );
}

TCP/IP Connection Example

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, 17, signature, buffer); // Register (Legacy only)
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);

⚠️ Legacy vs Adapter Separation

Legacy ECR integrations require:
- Register Terminal (txnType = 17)
- Start Session (txnType = 18)
Adapter/Middleware integrations (Local REST API, Cloud REST API) do not require registration or session steps.

Request and Response Details

When performing a transaction, include:

Date (ddMMyyHHmmss)
ECR Reference Number (String)
Amount (Integer in halalas, e.g., 100 = SAR 1.00)

Responses return:

Response Code (Approved/Failed)
Approval Code
Receipt Data

Transaction Type Codes

Code	Transaction Type
0	Purchase
1	Purchase with Naqd/Cashback
2	Refund
3	Authorization
4	Purchase Advice (Full)
5	Purchase Advice (Partial)
6	Auth Extension
7	Auth Void
9	Cash Advance
10	Reconciliation
11	Reversal
15	Bill Payment
17	Register (Legacy only)
18	Start Session (Legacy only)
19	End Session
23	Duplicate / Previous Txn
24	Check Status
25	Health Check