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SerialPort.DataBits Property


Gets or sets the standard length of data bits per byte.

Namespace:   System.IO.Ports
Assembly:  System (in System.dll)

public int DataBits { get; set; }

Property Value

Type: System.Int32

The data bits length.

Exception Condition

The port is in an invalid state.

- or -

An attempt to set the state of the underlying port failed. For example, the parameters passed from this SerialPort object were invalid.


The data bits value is less than 5 or more than 8.

The range of values for this property is from 5 through 8. The default value is 8.

The following code example demonstrates the use of the SerialPort class to allow two users to chat from two separate computers connected by a null modem cable. In this example, the users are prompted for the port settings and a username before chatting. This code example is part of a larger code example provided for the SerialPort class.

public static void Main()
    string name;
    string message;
    StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;
    Thread readThread = new Thread(Read);

    // Create a new SerialPort object with default settings.
    _serialPort = new SerialPort();

    // Allow the user to set the appropriate properties.
    _serialPort.PortName = SetPortName(_serialPort.PortName);
    _serialPort.BaudRate = SetPortBaudRate(_serialPort.BaudRate);
    _serialPort.Parity = SetPortParity(_serialPort.Parity);
    _serialPort.DataBits = SetPortDataBits(_serialPort.DataBits);
    _serialPort.StopBits = SetPortStopBits(_serialPort.StopBits);
    _serialPort.Handshake = SetPortHandshake(_serialPort.Handshake);

    // Set the read/write timeouts
    _serialPort.ReadTimeout = 500;
    _serialPort.WriteTimeout = 500;

    _continue = true;

    Console.Write("Name: ");
    name = Console.ReadLine();

    Console.WriteLine("Type QUIT to exit");

    while (_continue)
        message = Console.ReadLine();

        if (stringComparer.Equals("quit", message))
            _continue = false;
                String.Format("<{0}>: {1}", name, message));


public static void Read()
    while (_continue)
            string message = _serialPort.ReadLine();
        catch (TimeoutException) { }

.NET Framework
Available since 2.0
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