National Instruments PCI-8430 - Page 32

PCMCIAKits
ThePCMCIAserialhardwaregivesyouavarietyofsolutionsforserial
communication.ThePCMCIA-232interfacesworkwiththeRS-232
protocol,andthePCMCIA-485interfaces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.
ThePCMCIA-232isavailableinone-port,two-port,andfour-port
versions.ThePCMCIA-485isavailableinone-portortwo-portversions.
AllPCMCIAcardscomewithcablesforeachportthatterminatesina
standardDB-9connector.Throughoutthishelpfile,PCMCIAserial
interfacesreferstoallversionsoftheinterfaces.
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
reliablecommunicationwithtwoandfour-wiredevices.Formore
informationabouttransceivercontrolmodes,refertoRS-485Transceiver
Control.
AllPCMCIAserialhardwareusesstandard16550-compatibleUARTs
(UniversalAsynchronousReceiver/Transmitters)forcomplete
compatibilitywithstandardPCCOMports.Theserialhardwarecontains
FIFO(First-In-First-Out)bufferstoreducesusceptibilitytointerrupt
latencyforfastertransmissionrates.FullPlugandPlaycompatibility
allowsswitchlessconfigurationandinstallation.Formoreinformation
abouttheserialhardwarespecificationsandoperatingconditions,referto
theNISerialHardwareGuide.