Chapter 3
Signal Connections
3-2
ni.com
Table 3-1 summarizes the functions of the connectors on the NI 8255R.
Connectors
This section describes the connectors on the NI 8255R and includes pinouts
and signal descriptions.
IEEE 1394b Connector
The NI 8255R provides two direct-connect IEEE 1394b bilingual
connectors, which support IEEE 1394a and IEEE 1394b devices. The
connectors provide a reliable, high-frequency connection between the
NI 8255R device and up to two DCAM-compliant IEEE 1394 cameras.
To access the IEEE 1394b connectors on the NI 8255R device, use any
standard 9-pin IEEE 1394 cable.
Note
You can use a 6-pin to 9-pin cable or adapter with IEEE 1394a cameras to connect
the cameras to the IEEE 1394b ports.
ATX Connector
The ATX connector on the NI 8255R allows the 1394 devices that are
connected to the NI 8255R to draw power directly from the computer
power supply, instead of the PCI Express bus. The PCI Express bus has a
stricter current draw allowance than the computer power supply. Connect
the NI 8255R device to the computer power supply by connecting an
unused ATX power connector from within the computer chassis to the
ATX connector on the NI 8255R. The green LED on the front panel of the
NI 8255R device will illuminate when the ATX connector is connected to
the computer power supply and the computer is on.
Table 3-1.
NI 8255R Connector Functions
Peripheral
Connector
Function
IEEE 1394
9-pin IEEE 1394b bilingual
connector
Power and data connection to
IEEE 1394 devices
Camera Power
4-pin ATX computer power
connector
Power from PC power supply to
IEEE 1394b connectors
Digital Input/Output
44-pin female high-density
D-SUB connector
External TTL I/O,
External isolated I/O,
Power for isolated outputs