o  polling substate

    Specifies the state of a tributary as determined by the polling
    algorithm. This attribute applies only when the value of the
    link's protocol characteristic is set to control. The value of
    this attribute is affected by the value of the characteristic
    polling state. If the characteristic polling state is set to
    automatic, the value of this status attribute reflects the
    current state of the polling algorithm. For all other values of
    the polling state characteristic, the values of both attributes
    are the same.

    active      The tributary is active and responds with data when
                selected.

    dead        The tributary did not respond when selected within
                the appropriate timeout period, when already in
                the Dying or Inactive state. The tributary will be
                ignored until the station reinitializes.

    dying       The tributary, currently in the Inactive or Active
                state, has not responded within the appropriate
                timeout period when selected.

    inactive    The tributary has not sent any data when selected
                by the control station. However, the tributary has
                responded with an appropriate message when selected.

 o  protocol state

    State of the data link protocol with the remote station.

    halted         The protocol is stopped and no messages are being
                   exchanged with the remote station.

    maintenance    The protocol is off line and dealing with
                   maintenance messages only.

    running        The protocol is on line and is exchanging messages
                   with the remote station.

    starting       There is an attempt to initialize the protocol
                   between the local and remote stations. This uses
                   the STRT and STACK PDUs.

 o  state

    Operational state of the local logical station.

    off            The station is disabled.

    on             The station is enabled.

 o  uid

    Entity's unique identifier, which is generated when the entity is
    created.