What are the round pads on the bottom of a PCB?

There are several round pads on the PCB prototypes made by the manufacturer. They are marked Scx and labelled with TP. What are they?

PCB Assembly, PCB Testing
November 1, 2023

These test pads and the test points are probably used in different parts of the manufacturing process. For example,

The test points may be used for board-level testing and the test pads may be used for system-level testing. These are test pads designed for use with a pogo-pin test fixture, also known as a bed-of-nails test fixture. These fixtures have a specially shaped array of pogo-pins that press down and make contact with the test pads on the board under test.
Or, perhaps, the test pads are used for programming and/or debugging firmware, when the device under test is clamped into the bed-of-nails fixture.

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

Oliver Smith

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