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SettingRingIndicate(RI)andDataCarrier

Detect(DCD)withDeviceIoControl

TherearetwowaystosetandretrievetheseRS-232signals:

SetandreadtheNI-VISALineRIStateandLineDCDState

attributes.

TheNI-Serialsoftwareusesprogrammaticcontrolcodesandthe

DeviceIoControlWindowsfunctiontoretrievetheseRS-232

signals.

ToretrievetheseRS-232signalsusingtheDeviceIoControlWindows

function,completethefollowingsteps:

1. Addthefollowinglinestoyoursourcecode:

#include<winioctl.h>

#include<NiSerial.h>

NoteTheheaderfileNiSerial.hisincludedonyourNI-

SerialsoftwareCD.YoualsocanfinditintheNI-Serial

folderwhereyouinstalledyourNationalInstruments

software(typically,C:\ProgramFiles\NationalInstruments\NI-

Serial).

2. TheSERIAL_RI_OUTattributecanhavethefollowingvalues:

SERIAL_RI_ON

SERIAL_RI_OFF

3. TosettheRS-232signalRIwhenthetransceiverisinDCEmode,

usethefollowingcode:

DWORDl_ByteCount;

DeviceIoControl(

PortHandle,

NISERIAL_SET_RI,

(LPVOID)NULL,

0,

National Instruments PCI-8430 User Manual

Questions and Answers: