This attribute indicates the protocol state of the fax adaptor. This
attribute has one of the following values:
setup: Call setup state.
idle: Idle state only transmitting Synchronize (SYNC) frames.
bcsRx: Receiving Binary Coded Signal (BCS) packet from modem.
bcsTx: Transmitting BCS packet to modem.
msgRx: Receiving fax message from modem.
msgTx: Transmitting fax message to modem.