Summary:

How do I change the brightness on the Ingenico iSC250? 

Solution:

• Hold Clear and <minus> until the device reboots.
• During startup, on the gray Retail Base App info screen select:  2, 6, 3, 4, then  <Enter>
• Then <+> to get the menu
• Select Telium Manager
• Initialization
• Hardware
• Display
• Back Light, move the slider to adjust to desired brightness.