6100 BSC Programming Manual

6100 BSC Link and Station Management
LINE STATES AND TRANSITIONS
6100 BSC is realized as a "state machine." At a given time,
a station is in one of six major states. Application requests
and arriving data are "events" that can cause state transitions.
Only certain events are allowed in each state; for example, you
can't send data if the station is disconnected, and you can't
change line parameters unless the station is disconnected.
Figure 2-1 presents a simplified view of BSC states and
transitions. The rest of this section describes the states and
transitions in more detail. MULTILEAVING state is not shown
in the figure, but it is discussed in this section.
NOTE
The line states reported in a protocol trace are more
specific than those described here. For example, the READ
state actually has several substates. This section does not
provide information to help you decode trace data.
2-2