Final answer:
The last letter 'N' in the SYSCOM control number indicates 'Network'. It signifies that the control number is related to network components within the SYSCOM.
Step-by-step explanation:
The last letter in the SYSCOM control number S2 3EFF N represents the 'Network'. In such control number designations, letters are typically used to denote specific aspects or components related to the system or item being described. In this context, 'N' stands for Network, indicating that the control number is associated with network-related elements or characteristics within SYSCOM.