National Instruments PCI-8430 - Page 29

ENETKits
TheENETserialhardwaregivesyouavarietyofsolutionsforserial
communication.TheRS-232interfacesworkwiththeRS-232protocols.
TheRS-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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boards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serialENETinterfacescontainFIFO(First-In-First-Out)buffersto
reducesusceptibilitytointerruptlatencyforfastertransmissionrates.
Also,serialENETinterfacescontainadditionalonboardbufferstoreduce
susceptibilitytoEthernetnetworktraffic.
WithaserialENETinterface,yougainallthefeaturesinherentina
networkeddevice:fewercablingdistancerestrictions,devicesharing,
andcommunicationwithdevicesthroughouttheInternet.Inaserial
application,youusuallyarerestrictedtothedistancelimitationsofthe
RS-232,RS-422,orRS-485specifications.BecausetheserialENET
interfaceusesEthernet,youcanaddanunlimiteddistancetoyour
applicationbyexploitingthedistancesavailableusinganetworked
device.DevicesharingwithaserialENETinterfacehappensonaper-
portbasis.Thatis,althoughtheserialENETinterfacesupportsnetwork
connectionsfrommultiplehosts,eachserialportisassociatedwithonly
onehostatatime.
DynamicHostConfigurationProtocol(DHCP)isavailableonmany
networkstoconfigurenetworkparametersautomatically.DHCPsimplifies
theinstallationandconfigurationprocessfortheserialENET.Formore
informationaboutDHCP,refertoUsingDHCP.