National Instruments PCI-8430, Manual

Page: 116 / 237

Retrieving the RS-232 Transceiver State
The NI-Serial software returns which mode the RS-232 transceivers are
currently operating in, and whether the serial connection is valid.
Note Transceiver mode refers to the programmed mode.
Transceiver state refers to the physical state of the transceivers
(actual operating mode and whether valid or invalid).
There are two ways to retrieve the RS-232 transceiver state and
tranceiver mode:
Read the NI-VISA wire mode attribute to retrieve the transceiver
state and the NI-VISA IsPortConnected attribute to retrieve the
transceiver mode.
The NI-Serial software uses programmatic control codes and the
DeviceIoControl Windows function to retrieve the RS-232
transceiver state and transceiver mode.
To retrieve the RS-232 transceiver state 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 RS-232 transceiver state attribute is contained within a struct
of type
SERIAL_RS232_STATE
. The struct members and possible
values are shown below:
Member
Name Values
PortMode RS232_MODE_DTE
RS232_MODE_DCE
RS232_MODE_AUTO