This documentation is archived and is not being maintained.

SerialPort.DsrHolding Property

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

Gets the state of the Data Set Ready (DSR) signal.

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

public bool DsrHolding { get; }
/** @property */
public boolean get_DsrHolding ()

public function get DsrHolding () : boolean

Property Value

true if a Data Set Ready signal has been sent to the port; otherwise, false.

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 stream is closed. This can occur because the Open method has not been called or the Close method has been called.

This property is used in Data Set Ready/Data Terminal Ready (DSR/DTR) handshaking. The Data Set Ready (DSR) signal is usually sent by a modem to a port to indicate that it is ready for data transmission or data reception.

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