The Amiga Diagnostic ROM is used to debug and test Amiga mainboards. You replace the normal Kickstart ROMs with these DiagROMs and your Amiga boots into a diagnostic menu. From there you can select many different testing routines for checking Chip- and Fast-RAM, Serial and Parallel ports, mouse and joystick ports, CIA chips, IRQ channels, testing audio and video output and much more. The Parallel and Serial port loopback adapters are also usable for Amiga Test Kit which can be booted from floppy disk.
The Amiga 1200, 3000 and 4000 models have two ROM sockets. The following list shows which ROM you need to put into which socket:
A1200: HI=U6A, LO=U6B
A3000: HI=U181, LO=U180
A4000: HI=U175, LO=U176
Important note for Amiga 1000 users only: The parallel and serial port dongles do not comply with the special Amiga 1000 ports. However, you can use one of these parallel port adapters to use the dongle on the Amiga 1000. A serial port adapter for the Amiga 1000 is currently in the design phase.