I don't fully understand your question. A USB cable. by itself, is a
passive aggregation of wire and connectors. If you just plug the
cable into a computer nothing will happen.

The other end of the USB cable must be plugged into something (such as
a USB hub, CF/SD card reader, printer, etc.) before the computer will
"see" what's there. If the device to which the other end is plugged-in
is a USB-to-RS232 converter, the computer and the device will initiate
some hand-shaking and (possibly) install a driver for the device if
one isn't already installed.

As far as RS232 goes, the only identification that could/would be
returned to the computer would be whatever your application program
has requested from the RS232 device. This is very device/application
dependent. FOr example, my chip/EPROM burner doesn't do anything on
the RS232 line until the app program begins talking to it. Same thing
with my telescopes which use RS232 for remote control.

If you could supply some more info about what it is you're attempting
to connect up, more help could be provided.