These numbers (640 x 480, 832 x 624, and 1024 x 768) represent standard computer display resolutions that an NEC MultiSync monitor is programmed to support across various analog or digital video timings.640 x 480: Standard VGA resolution (4:3 aspect ratio).832 x 624: Classic Macintosh high-resolution display mode (75 Hz), commonly supported by multi-frequency monitors using a Mac adapter.1024 x 768: XGA resolution (4:3 aspect ratio), often listed as a supported or optimum preset mode for many legacy and enterprise NEC displays.If you are trying to troubleshoot a display issue, connect a specific device, or find a manual, please share the exact model number of your NEC MultiSync monitor so I can give you the correct setup steps.