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SerialPort.ReadTimeout Property

Note: This property is new in the .NET Framework version 2.0.

Gets or sets the number of milliseconds before a time-out occurs when a read operation does not finish.

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

public int ReadTimeout { get; set; }
/** @property */
public int get_ReadTimeout ()

/** @property */
public void set_ReadTimeout (int value)

public function get ReadTimeout () : int

public function set ReadTimeout (value : int)

Property Value

The number of milliseconds before a time-out occurs when a read operation does not finish.

Exception typeCondition


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 read time-out value is less than zero and not equal to InfiniteTimeout.

The read time-out value was originally set at 500 milliseconds in the Win32 Communications API. This property allows you to set this value. The value can be set to 0 for immediate return from a read, set to any positive value, or set to InfiniteTimeout, which is the default. This property does not affect the BeginRead method of the BaseStream.

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.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

.NET Compact Framework

Supported in: 2.0

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