The term radio-wire integration (RWI) is being replaced
by Net Radio Interface (NRI). The functions and operations remain the same,
but the name change more closely reflects the service provided. NRI systems
can be secured through the use of the Vinson (KY-57 and KY-58) secure systems.
The HYX-57 provides the interface for the KY-57 to a standard 2-
or 4-wire telephone transmission line, but it does not encrypt or decrypt.
This is done by the KY-57. Distance between HYX-57s should be no greater
than 16 kilometers (10 miles). If a secure wire line is required over a
distance greater than 16 kilometers (10 miles), two HYX-57s can be placed
back-to-back to double the range.
