INT 15 - MultiDOS Plus - WAIT FOR EVENT
AX = 1E02h
DX = event/trigger number (00h-3Fh)
Return: AH = status
00h successful
01h invalid event/trigger number
Note:   if the event counter is zero, the task is suspended until the event is
triggered with AX=1E01h; else, the counter is decremented and the
call returns immediately
SeeAlso: AX=1E01h

See also: 151E00

151E02 - MultiDOS Plus - WAIT FOR EVENT