|Quoting RICARIZA (Thread starter):
What exactly is the function of the HFS-900D HF Data Link Communications System, the CPL-920D HF Coupler Unit
I guess I found the answer to my question:
Rockwell Collins HFS-900D Data Radio provides a low-cost, long-range data link system for fleets operating in oceanic, polar and remote land areas. When paired with the Rockwell Collins CPL-920D Digital Antenna Coupler, the HFS-900D high frequency data link (HFDL) system provides the high reliability system needed for HFDL applications.
[Edited 2007-08-21 22:53:20]