Specifies the port's mode of operation.
auto: Automatically detect the port mode
upon insertion.
fdxCport: Transmit Immediate (full-duplex)
Concentrator Port
fdxStation: Transmit Immediate (full-duplex)
Station emulation
hdxCport: Token Passing Protocol (half-duplex)
Concentrator Port
hdxStation: Token Passing Protocol (half-duplex)
Station emulation
riro: RingIn/RingOut mode. (wsx5031 only)