Custom Scan Codes (Standard 8)

7/8/2014

Review the custom scan codes commands in Embedded Lockdown Manager (ELM) Keyboard Filter in Windows Embedded 8 Standard (Standard 8).

You can define custom scan codes to block specific keyboard keys. You can use the Embedded Lockdown Manager (ELM) to add, remove, block, and unblock custom scan codes.

Scan Codes

When a key is pressed on a physical keyboard, the keyboard sends a scan code to the keyboard driver. The driver then sends the scan code to the OS and the OS converts the scan code into a virtual key based on the current active layout. The layout defines the mapping of keys on the physical keyboard, and has many variants. A key on a keyboard always sends the same scan code when pressed, however this scan code can map to different virtual keys for different layouts. For example, in the English (United States) keyboard layout, the key to the right of the P key maps to { (left brace). However, in the Swedish (Sweden) keyboard layout, the same key maps to Å.

Create a Custom Scan Code

A custom scan code consists of a combination of zero or more modifiers and a scan code. The modifier keys consist of Alt, Ctrl, Shift, and the Windows Logo key. For each modifier, you can specify the left or right keys independently, or specify both versions of the key.

To create a custom scan code

  • In the Custom Shortcut dialog box, do one of the following:

    • Select Type the key to reveal its Scan Code, select the text box at the bottom of the dialog box, and press the key to block.
      The hexadecimal scan code for the key is filled in automatically.
    • Select Enter Scan Code by number, select the text box at the bottom of the dialog box, and enter the hexadecimal value of the scan code to block.

The ELM sets the new custom scan code to be blocked by default.

Note

Power management keys, such as Power, Sleep, and Wake Up, may not have scan codes. You can instead use Group Policy to block power management keys that do not have scan codes.

Commands

On this screen, you can use the following commands:

  • Block all keys
    Blocks all custom defined scan codes.
  • Allow all keys
    Unblocks all custom defined scan codes.
  • Add custom scan code
    Opens a dialog box in which you can specify a custom scan code to add.
  • Delete blocked key
    Removes the selected custom scan code. If the scan code was blocked, it becomes unblocked.
  • Block this key
    Blocks the currently selected custom scan code.
  • Allow this blocked key
    Unblocks the currently selected blocked custom scan code.

See Also

Concepts

Keyboard Filter