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State of the CD, CTS, DSR, and RI pins


PinStatus is a structure array that contains the fields CarrierDetect, ClearToSend, DataSetReady and RingIndicator. These fields indicate the state of the Carrier Detect (CD), Clear to Send (CTS), Data Set Ready (DSR) and Ring Indicator (RI) pins, respectively. For more information about these pins, see Serial Port Signals and Pin Assignments.

PinStatus can be on or off for any of these fields. A value of on indicates the associated pin is asserted. A value of off indicates the associated pin is unasserted. A pin status event occurs when any of these pins changes its state. A pin status event executes the call back function specified by PinStatusFcn.

In normal usage, the Data Terminal Ready (DTR) and DSR pins work together, while the Request to Send (RTS) and CTS pins work together. You can specify the state of the DTR pin with the DataTerminalReady property. You can specify the state of the RTS pin with the RequestToSend property.

For an example that uses PinStatus, see Example — Connecting Two Modems.


Read only


Data type




The associated pin is unasserted.


The associated pin is asserted.

The default value is device dependent.

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