[Elecraft] K3s question

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For reasons unknown to me, I am unable to view the K3s DATASHEET or FAQ.  Looking at the review of the K3s photo I see a USB connector and an Ethernet connector labeled as rs232/P3.  Am I correct?  For those that can read the datasheet and/or FAQ, what does the USB do and what does the Ethernet connector do?  I am not a computer wizard so be gentle.

73, Steve, K4FJ