Bits 0-3 are used by the classroom-based command lists to indicate that or check whether a teacher has arrived at the classroom door to start the lesson.

Bit(s)	Meaning if set
0	Teacher has arrived at the Map Room
1	Teacher has arrived at the Reading Room
2	Teacher has arrived at the Exam Room
3	Teacher has arrived at the White Room
4-6	Unused
7	EINSTEIN is speaking (set by 31919; checked by 31162 and 31944; reset by 31178)