The standard 20-pin connector pinout is defined by ARM. The V9 schematic maps this as follows:
When you analyze a typical "J-Link V9 clone" schematic (many are derived from early SEGGER design leaks or diligent reverse engineering), you will consistently find the following architecture. jlink v9 schematic
This information is for educational purposes regarding debugger architecture. SEGGER holds the IP for J-Link. Do not use this to manufacture commercial clones. The standard 20-pin connector pinout is defined by ARM
Even with a perfect schematic, the J-Link V9 relies on . The LPC4322 contains a bootloader that talks to the SEGGER DLL on your PC. The DLL sends encrypted firmware updates. jlink v9 schematic