The following illustration shows the layout of the system board assembly which contains the firmware and 
RoT security module, system I/O board, processor board, fan board and PIB board.  
Figure 13. System-board-assembly layout
1  System I/O board
2  Firmware and RoT security module
3  Processor board 4  Fan board
5  PIB board
• 
“System-board-assembly connectors” on page 33
•  “System-board-assembly switches” on page 34
•  “System-board-assembly LEDs” in User Guide or Hardware Maintenance Guide
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ThinkSystem SR635 V3 System Configuration Guide