Jumpers, switches, and buttons on standard I/O book board
This topic provides the location and information about the jumpers, switches, and buttons on the standard I/O book board.
The following illustration shows the location of the switches, jumper, and button on the server.

The following table describes the jumper on the standard I/O book board.
| Jumper number | Jumper name | Jumper setting |
|---|---|---|
| J35 | IMM security jumper |
|
Note If no jumper is present, the server responds as if the pins are set to the default. | ||
The following table describes the functions of the SW1 switch block on the standard I/O book board.
| Switch number | Default position | Description |
|---|---|---|
| 1 | Off | Power-on password override. Changing the position of this switch bypasses the power-on password check the next time the server is turned on and starts the Setup utility so that you can change or delete the power-on password. You do not have to move the switch back to the default position after the power-on password in overridden. Changing the position of this switch does not affect the administrator password check if an administrator password is set. See Passwords for additional information about passwords. |
| 2 | Off | Reserved |
| 3 | Off | Reserved |
| 4 | Off | Reserved |
| 5 | Off | Reserved |
| 6 | Off | Reserved |
| 7 | Off | Force UEFI backup bank. Changing the position of the switch to ON will force the system to boot from the backup UEFI bank. |
Important:
- Before you change any switch settings or move any jumpers, turn off the server; then, disconnect all power cords and external cables. Review the information in Safety, Installation guidelines, Handling static-sensitive devices, and Turning off the server.
- Any standard I/O book board switch or jumper blocks that are not shown in the illustrations in this document are reserved.
The following table describes the functions of the button on the standard I/O book board:
| Button name | Function |
|---|---|
| NMI button | This button is on the rear of the standard I/O book. Press this button to force a nonmaskable interrupt to the microprocessor. You might have to use a pen or the end of a straightened paper clip to press the button. You can also use it to force a blue-screen memory dump (use this button only when you are directed to do so by Lenovo Support). |