National Instruments PCI-8430, Manual

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PXI Kits
The PXI serial hardware gives you a variety of solutions for serial
communication. The RS-232 boards (PXI-8430, PXI-8432, PXI-8420, and
PXI-8422) work with the RS-232 protocol. The RS-485 boards (PXI-8431,
PXI-8433, PXI-8421, and PXI-8423) work with the RS-422 and RS-485
protocols. You can use the RS-232 ports for serial communication up to
distances of 50 ft. You can connect the RS-485 ports to up to 31 devices
using serial cable lengths up to 4,000 ft.
Additionally, the PXI serial boards are available in two-port, four-port,
eight-port, and 16-port versions. The two-port versions use DB-9
connectors. The four-port versions use 10-position modular jacks to
provide all four connections on a single front panel. Optional cable
accessories convert the 10-position modular jacks to either DB-9 or DB-
25 connectors with standard pinouts. The eight-port versions use adapter
cables to convert the 68-pin connector on the board to eight DB-9
connectors. The PXI-8430/16 uses two adapter cables to convert the two
68-pin connectors on the board to 16 DB-9 connectors. The PXI-8420/16
uses a breakout box to convert the 100-pin connector on the board to 16
DB-9 connectors. Throughout this help file,
PXI serial boards refers to all
versions of the PXI serial boards.
The isolated PXI boards are designed for applications in harsh
environments. Isolated ports provide reliable communication in situations
involving ground loops from different ground levels or high common
mode voltage induced on the lines in noisy environments. Nonisolated
ports may not provide reliable communication in those situations. The
isolation between each communication port and the host PC ensures the
safe operation of the PC and the devices connected to other ports on the
same board, in case of accidental high voltages or line surges on
communication lines.
The RS-232 ports are DTE. In the RS-232 specification, Data Terminal
Equipment (DTE) and Data Communications Equipment (DCE) refer to
the types of equipment on either end of a serial connection. In general,
DTE and DCE refer to computer equipment and modems, respectively.
For more information about cabling a RS-232 port to other devices, refer
to
RS-232 DTE vs. DCE .
The RS-485 ports support four hardware transceiver control modes for