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SerialPort.DsrHolding Property


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

 property bool DsrHolding { bool get(); };
public bool DsrHolding { get; }
public bool DsrHolding { get; }
member this.DsrHolding : bool
member this.DsrHolding : bool
Public ReadOnly Property DsrHolding As Boolean

Property Value

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



The port is in an invalid state.


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.

Applies to