How to acquire synchronous serial data?

[Pont68]

I am trying to acquire synchronous serial data (SDLC protocol, RS-485/422, bi-phase mark) at 1.2Mb/s using a Real-Time Labview system?  I bought a 8433/4 card because it offered the isolation I needed but have found that it operates only asynchronously.  Any suggestions would be appreciated. 

[Snowman 6008]

Serial is an asynchronous protocol. You cannot do
deterministic serial communication. Maybe if you share more information about
what you are trying to accomplish we can help you pick a different protocol.
What are your timing constraints?

[Pont68]

SDLC stands for Synchronous Data Link Control and it is used for serial communication so I'm confused on how serial data can't be synchronous.  Here are some cards that work in this format: http://www.generalstandards.com/serialio3.php?config=yellow_green.  

I have a cabinets which will be sending data in this protocol and want to be able to monitor it using a Labview Real-time system (8108RT controller) along with some analog and digital signals (which I have separate cards for).  I'm not sure why I couldn't put Visa Read VIs in a deterministic loop.  

[Pont68]

Does anybody know of any companies that provide SDLC cards that are knowlegable and willing to write drivers for use with LabView Real-Time OS? 

[Snowman 6008]

It looks like there is a company that has provided another forum poster a custom solution to this problem: http://forums.ni.com/ni/board/message?board.id=140&message.id=1282&requireLogin=False