Dummy board and Extender board custom circuit board manufacturers
A dummy board provides a minimal interface. This type of diagnostic board in intended to confirm that the interface is correctly implemented. For example, a PC motherboardmanufacturer can test PCI functionality of a PC motherboard by connecting a dummy PCI board into each PCI slot on the motherboard
An extender board (or board extender, card extender, extender card) is a simple circuit board that interposes between a card cage backplane and the circuit board of interest to physically 'extend' the circuit board of interest out from the card cage allowing access to both sides of the circuit board to connect diagnostic equipment such as an oscilloscope or systems analyzer. For example, a PCI extender board can be plugged into a PCI slot on a computer motherboard, and then a PCI card connected to the extender board to 'extend' the board into free space for access. This approach was common in the 1970s and 1980s particularly on S-100 bus systems.
The concept can become unworkable when signal timing is affected by the length of the signal paths on the diagnostic board, as well as introducing Radio Frequency Interference (RFI) into the circuit under test because of a lack of adequate shielding.
The use of extender boards is declining because of the wider use of multilayer flexible circuit boards and overall cheaper components, particularly in the consumer end of the electronics market