From e830e43c363323a009836e52ff1230a8405f2845 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20M=C3=BCller?= <webmaster@am-wd.de>
Date: Wed, 17 Jul 2024 18:00:16 +0200
Subject: [PATCH] Clearified/fixed description of different protocol
 implementations

---
 .../Protocols/RtuOverTcpProtocol.cs              | 16 +++++++++-------
 AMWD.Protocols.Modbus.Common/README.md           |  9 +++++++--
 AMWD.Protocols.Modbus.Tcp/README.md              |  4 ++--
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs b/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
index 67fcb6a..72089b4 100644
--- a/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
+++ b/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
@@ -6,11 +6,13 @@ using AMWD.Protocols.Modbus.Common.Contracts;
 namespace AMWD.Protocols.Modbus.Common.Protocols
 {
 	/// <summary>
-	/// Implementation of the Modbus RTU over TCP protocol.
+	/// Implementation of the Modbus RTU over Modbus TCP protocol.
 	/// </summary>
 	/// <remarks>
 	/// The Modbus RTU over Modbus TCP is rarely used.
-	/// It is a non-standard variant of Modbus TCP that includes the Modbus RTU CRC at the end of the message.
+	/// It is a non-standard variant of Modbus TCP that includes wrapps a Modbus RTU message within a Modbus TCP message.
+	/// <br/>
+	/// Definition found on <see href="https://www.fernhillsoftware.com/help/drivers/modbus/modbus-protocol.html">Fernhill Software</see>.
 	/// </remarks>
 	public class RtuOverTcpProtocol : IModbusProtocol
 	{
@@ -475,16 +477,16 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			// Function code
 			request[7] = (byte)ModbusFunctionCode.WriteSingleRegister;
 
-			byte[] addrBytes = register.Address.ToBigEndianBytes();
-			request[8] = addrBytes[0];
+			byte[] addrBytes = register.Address.ToBigEndianBytes();
+			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
-			request[10] = register.HighByte;
+			request[10] = register.HighByte;
 			request[11] = register.LowByte;
 
 			// CRC
-			byte[] crc = RtuProtocol.CRC16(request, 6, 6);
-			request[12] = crc[0];
+			byte[] crc = RtuProtocol.CRC16(request, 6, 6);
+			request[12] = crc[0];
 			request[13] = crc[1];
 
 			return request;
diff --git a/AMWD.Protocols.Modbus.Common/README.md b/AMWD.Protocols.Modbus.Common/README.md
index ce2a2f2..ba38c91 100644
--- a/AMWD.Protocols.Modbus.Common/README.md
+++ b/AMWD.Protocols.Modbus.Common/README.md
@@ -59,8 +59,8 @@ Here you have the specific default implementations for the Modbus Protocol.
 
 - ASCII
 - RTU
-- RTU over TCP
 - TCP
+- [RTU over TCP]
 
 **NOTE:**    
 The implementations over serial line (RTU and ASCII) have a minimum unit ID of one (1) and maximum unit ID of 247 referring to the specification.
@@ -68,4 +68,9 @@ This validation is _not_ implemented here due to real world experience, that som
 
 ---
 
-Published under MIT License (see [**tl;dr**Legal](https://www.tldrlegal.com/license/mit-license))
+Published under MIT License (see [**tl;dr**Legal])
+
+
+
+[RTU over TCP]: https://www.fernhillsoftware.com/help/drivers/modbus/modbus-protocol.html
+[**tl;dr**Legal]: https://www.tldrlegal.com/license/mit-license
diff --git a/AMWD.Protocols.Modbus.Tcp/README.md b/AMWD.Protocols.Modbus.Tcp/README.md
index c459fe3..8ce403b 100644
--- a/AMWD.Protocols.Modbus.Tcp/README.md
+++ b/AMWD.Protocols.Modbus.Tcp/README.md
@@ -23,14 +23,14 @@ float voltage = registers.GetSingle();
 Console.WriteLine($"The voltage of device #{unitId} between L1 and N is: {voltage:N2}V");
 ```
 
-If you want to use the `RTU over TCP` protocol instead, you can do this on initialization:
+If you have a device speaking `RTU` connected over `TCP`, you can use it as followed:
 
 ```csharp
 // [...]
 
 using var client = new ModbusTcpClient(host, port)
 {
-	Protocol = new RtuOverTcpProtocol();
+	Protocol = new RtuProtocol()
 };
 
 // [...]