# Modbus RTU Over TCP

Modbus RTU is a protocol developed for serial communication layer. Unlike Modbus TCP, it does not contain the MBAP header. It is used to communicate with serial port (RS232 or RS485) devices using Modbus RTU protocol. Since it works on TCP / IP application layer, it is used with transparent serial-ethernet converters or terminal servers.

![Figure 1 : Modbus RTU Over TCP](https://3585470428-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LLGnZudlzfM63QD-_cp%2F-Ll5xPftxo2HNwivMOSG%2F-Ll5xkrx__DWoFoqa_UR%2Fimage.png?alt=media\&token=236e20ef-edd9-4c7d-9616-69e359c96c42)

As shown in Figure 1, inSCADA is connected to a terminal server as a Master via Modbus RTU Over TCP protocol. In the terminal server link layer, Ethernet performs serial conversion and transparency. In this way, protocol messages can be transmitted and communication can be provided between inSCADA and the device.

The use of Modbus RTU Over TCP in the inSCADA platform is identical to the configuration steps described in using Modbus TCP. Simply select Modbus RTU Over TCP as the protocol. See [Modbus TCP.](https://inscada.gitbook.io/ins/en-1/communication-protocols/modbus/modbus-tcp)


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