National Instruments PCI-8430 - Page 103

Two-WireMode:AutoControl
Inthismode,theserialhardwaretransparentlyenablesthetransmitter
andreceiverinatwo-wiresystem.Usethismodetoremovetheburden
oftransceivercontrolfromyourapplication.Thehardwareautomatically
enablesthetransmitterforeachbytetobetransmitted.Also,the
hardwaredisablesthereceiverwheneverthetransmitterisenabled,so
youdonotreceivethepacketssentfromyourtransmitter.
NoteWhenyouarecommunicatingwithatwo-wiredevice,
NationalInstrumentsrecommendsthatyouusethetwo-wireAuto
Controlmode.Becausethismodehandlesthetransmitter/receiver
enablingforatwo-wireconnectioninyourhardware,itreducesthe
softwareoverheadrequiredtoperformthisoperationinyour
applicationprogram.
Formoreinformationaboutserialcommunicationintwoorfour-
wiremodes,refertoSerialCommunicationIssues.