synchronous interface card suggestions

[John Ackermann N8UR <jra@febo.com>]

Hi --

I'm trying to implement a wireless point-to-point link  using a pair of 
radios that have a synchronous RS-422 interface.  The radios operate at 
128kbps and provide clock signals, etc.

Can anyone suggest a source for such a card -- preferably inexpensive as 
this is a personal project -- that has Linux support?

Thanks,

John
jra@febo.com