New Description
Pop'n HD cabinets use a variant called "IO-2-R",
which presumably has modifications to eliminate the warm up voltage for the lamps.
Pop'n SD cabinet variants of the IO-2 have 4 dipswitches, among which only the 4th one has a known use. When windows starts it runs a program called "boot.exe" which reads the DIP4 value. If it is in the up position, resolution is changed to a 480i 60Hz 15 kHz signal. If it is in the down position or if no IO-Board was found, it switches to a 480p 60Hz signal (this mode is mislabeled as 75Hz in the graphics device driver, but signal has been confirmed to be indeed 60Hz. This was probably done as a hack so they could switch between 15kHz or 31kHz signals by using values "60" or "75" in the ChangeDisplaySettingsEx() windows API call).
Note: older Pop'n Music cabinets (type A, B and C) have a video amp on the power distribution board (aka "relay circuit box"), which led to a common misconception that the IO-2 was processing video signals. In reality, for these cabinets the video signal was fed directly from the PC motherboard to the power distribution board. The IO-2 itself has no means to process video signals.
Old Description
Pop'n HD cabinets use a variant called "IO-2-R",
which presumably has modifications to eliminate the warm up voltage for the lamps.
Pop'n SD cabinet variants of the IO-2 have 4 dipswitches, among which only the 4th one has a known use. When windows starts it runs a program called "boot.exe" which reads the DIP4 value. If it is in the up position, resolution is changed to a 480i 60Hz 15 kHz signal. If it is in the down position or if no IO-Board was found, it switches to a 480p 60Hz signal (this mode is mislabeled as 640x480x75 in the graphics device driver, but signal has been confirmed to be indeed 60Hz. This was probably done as a hack so they could switch between 15kHz or 31kHz by using values "60" or "75" in the ChangeDisplaySettingsEx() windows API call).
Note: older Pop'n Music cabinets (type A, B and C) have a video amp on the power distribution board (aka "relay circuit box"), which led to a common misconception that the IO-2 was processing video signals. In reality, for these cabinets the video signal was fed directly from the PC motherboard to the power distribution board. The IO-2 itself has no means to process video signals.