Chapter1 Introduction
SerialHardware and Software for Windows 1-6 ni.com
PCMCIA Kits
The serialhardware gives you a variety of solutions for serial
communications. The PCMCIA-232 interfaces work with the RS-232
protocols,and the PCMCIA-485 interfaces work w ith theRS-422 and
RS-485 protocols. You can use the PCMCIA-232 hardware for serial
communicationup to distances of 50 ft. You can connect the PCMCIA-485
hardwarewi th up to 31 devices using serial cable lengths up to 4,000 ft.
The PCMCIA-232 is availablewith one, two, or four ports. The
PCMCIA-485 is availablein a one-port version or two-port version.
AllP CMCIA cards come with cables for each port that terminates in a
standard DB-9 D-Sub connector.Throughout this manual, references to
PCMCIA serial interfacesgenerally refer to all versions of the interfaces.
The PCMCIA-485interfaces support four hardware transceiver control
modes for reliable communication with two-wire and four-wire devices.
Refert o Chapter 6, Using Your Serial Hardware, for more information
about transceivercontrol modes.
All of the serialh ardwareuses standard 1655 0-compatible UARTs
(UniversalAsynchronous Receiver/Transmitters) for 100 percent
compatibility with standardPC COM ports. The serial hardware contains
FIFOs (First-In-First-Out buffers)fo r reduced susceptibility to interrupt
latencyand faster transmission rates. Full Plug and Play compatibility gives
you the convenienceof switchless configuration and installation. Refer to
Appendix E, Specifications, for more information about the serial hardware
specificationsand operating cond itions.
AT Kits
The serialhardware gives you a variety of solutions for serial
communications.The AT-232 boards work with the RS-232 protocols, and
the AT-485 boards work with theRS-422 and RS-485 protoco ls.You can
usethe AT-232 hardware for serial communication up to distances of50 ft.
You can connectthe AT-485 hardware with up to 31 devices using serial
cable lengths up to 4,000 ft.
The ATboards are available in three different versions:
•Shared IRQ: All ports ont he board share the same IRQ.
•Isolated: All ports on the board are isolated and share the same IRQ.