I am not sure what that DIP Switch does (Unit identification for multiplayer games?) but the Red LED is power and the Green LED is IO activity. Update 16th October 2022: I forgot to mention that on the Type X4 units that I own that there’s a PCIe watchdog board (also known as the FastIO board) that has a DIP Switch and 2 LEDs. If you set the Type X4 BIOS to “Developer” mode, it will allow you to actually boot your own Windows/Linux installation on your TypeX4. To enable Developer Mode, you need to access the BIOS Setup Menu which is password protected via CTRL+ALT+F9. However, if you’re like me and like to play around with settings that you shouldn’t, then if you have your hands on a Type X4 that’s been decommissioned from overseas you can enable a “Developer Mode” which allows you boot from USB, LAN and other boot options. Normally, Type X-series arcade base units do not allow booting from USB/LAN or even show the Boot Menu. This is something interesting I found while playing around with my Taito Type X4.
