INT 2F - DR-DOS 6.0 TaskMAX - REGISTER/UNREGISTER TASK MANAGER
AX = 2704h
DL = subfunction
00h unregister task manager
01h register task manager
Return: DL = status
00h registered
01h unregistered
Notes:  a task manager replaces TaskMAX's menu system with its own user
interface; while one is registered, the TaskMAX hotkeys and
Ctrl-Alt-Del invoke the manager rather than the built-in menu system
unregister the task manager before terminating it

See also: 2F2705

2F2704 - DR-DOS 6.0 TaskMAX - REGISTER/UNREGISTER TASK MANAGER