The port can be configured to operate in either
half or full duplex mode. The values are:
halfDuplex(1)...half duplex mode
fullDuplex(2)...full duplex mode
The read-back channel status from hardware are:
none(0).........link down or port disabled.
halfDuplex(1)...half duplex mode
fullDuplex(2)...full duplex mode
The port media type (expansion or regular)
and port link type (trunk or feeder) determine
value of this object.
The port can not set to half duplex mode
if the port connect mode is m200e(4).
However, the value of this parameter may be
automatically set whenever the expansion port
is connected (e.g. cascade connecting device).