An MAI-OC session functions as a true SNA LU-type 1, and adheres to the protocols described in the IBM publication 3767 Component Description.
When MAI-OC has a session with JES2 or JES3, it appears as a 3776-type RJE device. This is still an LU-type 1, and the protocols used are a subset of those described above.
As MAI-OC is simulating a real terminal, it is possible to get a logical keyboard locked condition in which MAI‑OC is, for instance, waiting for a response from the application. At this time, the MAISEND command cannot be used to send data to the application, and if entered will be rejected with an appropriate error message.
The SHOW MAI command can be used to determine the session states of MAI sessions. Information given includes whether the keyboard is locked or unlocked, the SNA bracket state, and the general session state. Abbreviations used for states in the display are generally those used in the 3767 Component Description:
In Bracket
Between Brackets
Begin Bracket Pending
Send State (can send to application)
Receive State (cannot send)
Waiting for a definite response (cannot send)
Standby State (can send).
Indeterminate state (state change in progress or not in session).
The CON field in the display may contain the following:
Session established and available.
Session not yet established.
Session established but keyboard locked, because session state is not such that data may be sent.