A communications system includes a physical layer hardware unit and a processing
unit. The physical layer hardware unit is adapted to communicate data over a communications
channel in accordance with assigned transmission parameters. The physical layer
hardware unit is adapted to receive an incoming signal over the communications
channel and sample the incoming signal to generate a digital received signal. The
processing unit is adapted to execute a standard mode driver in a standard mode
of operation and a privileged mode driver in a privileged mode of operation. The
standard mode driver includes program instructions adapted to extract control codes
from the digital received signal and configure the physical layer hardware assigned
transmission parameters based on the control codes. The privileged mode driver
includes program instructions adapted to independently extract secure control codes
from the digital received signal, determine an operational characteristic of the
physical layer hardware unit, and signal a security violation in response to the
operational characteristic being inconsistent with the secure control codes.