NOTE: You can render your computer unusable if you do the wrong thing to the registry. If you are not familiar with editing the registry, you should follow these instructions precisely; better yet, you should find someone who is familiar with editing the registry.

Normally, touch will not function if any of the following serial signals are missing: TD (pin 3), DSR (Pin 6) or CTS (pin 8). Disabling handshaking, by adding a HardwareHandshake value to the Elo registry and setting it to zero, will allow touch to function if any of the above signals are missing. At a minimum, RD (pin 2) and ground (pin 5) must be connected. A reboot is required after adding the registry value.

To disable hardware handshaking:

Start here for BOTH Windows XP and 2000:

For Windows XP:

• Click the Edit item in the Menu, select New, select DWORD value
  • a New Value is created and highlighted
• Click Edit in the Menu, then select Rename
  • Enter HardwareHandshaking (use exact case and spelling)
    • The New value should be renamed
  • The value should have been created as 0. This is the value required to disable handshaking.
    • If you wanted to modify the value, you would click the name to highlight it, then select Modify from the Edit menu.
      • A value of 1 enables hardware handshaking. In this case, DSR and CTS signals must be asserted (pins 6 and 8 of a DB9 connector), and TD, RD and ground must be connected (pins 3, 2 and 5).
      • A value of 0 disables hardware handshaking.  In this case, only RD and ground are required (pins 2 and 5 of a DB9 connector)
• Close the registry and reboot the machine

For Windows 2000:

• Click the Edit item in the Menu, select Add Value
  • The Add Value window is shown
    • Type HardwareHandshaking in the Value Name box
    • Click the drop-down arrow to the right of the Data Type box, select REG_DWORD
    • Click OK
  • The DWORD Editor window is shown
    • Enter 0, click OK
  • The new value is displayed in the list
• Close the registry and reboot the machine