National Instruments PCI-8430 - Page 198

HowdoIuse9databitframing?
WhileNI-Serialsoftwareandhardwaredirectlysupportsonly5,6,7,and
8databits,itmaybepossibletousetheparityfunctiontocreateaninth
databit,dependingonyourapplication.Tocreateandcontrolaninth
databit,enableparityandsetparitymarkorparityspaceforaninthbitof
eithera1or0,respectively.However,youmustdothiseverytimethe
ninthbitchangesstate,andthusitmaynotworkforhigh-throughput
applications.