You really MUST plan to use a measurement device that allows hw-timed clocking of your data. You simply won't be able to accomplish that kind of timing with both accuracy and reliability in software. Not in LabVIEW at least, though its due more to the OS'es it runs on than LV itself.
It sounds like you're describing a 2-bit measurement. 1 bit is the serial data bit and the other 1 bit is the 125 kHz clock to tell when to register the data bit. You would assemble these bits into 32-bit words as they come in. Is this correct? If so, a simple and cheap solution is in an M-series board that allows for hw-clocked digital input. The cheapest is the PCI-6220. You could also probably do the measurement with a single analog input channel if you already have such hw around. It'd just require some extra post-processing to convert from voltage to digital Hi/Lo.
If you need to read in a full 32-bit port at a 125 kHz rate, then the cheapest NI DAQ board I found that looks capable is the PCI-6224.
If your budget is really really tight and you're good with a soldering iron, I imagine there's some other nifty ways...
-Kevin P.
ALERT! LabVIEW's subscription-only policy came to an end (finally!). Unfortunately, pricing favors the captured and committed over new adopters -- so tread carefully.
