Lenovo ThinkServer TD200x - Manual (Page 52)

v If the operating system stops functioning, you can press and hold the
power-control button for more than 4 seconds to turn off the server.
v The IMM can turn off the server as an automatic response to a critical system
failure.
v You can turn off the server through a request from the IMM.
36 ThinkServer TD200x Types 3719, 3821, 3822, and 3823: Installation and User Guide