Forget about RS-232.Modern embedded boards are designed to be used with USB to serial adaptors.What does "serial" mean here? All the USB-to-serial devices I've seen have, I _think_, been RS-232 in everything except the connector (they're typically DE-9 instead of DB-25).
I think what this refers to is a typical USB to TTL level serial adapter. "USB to serial" does imply RS-232, even though most kids wouldn't think so.
John