so need a DB9-to-GPIO adapter cable, which is an
   inexpensive passive cable that you can find online.
</p>
<p>
   If your PC doesn't have a physical serial port, you can still connect to
   the Pico's UART port, using a USB-to-UART adapter cable.  Unlike the DB9-to-GPIO
   cable, a USB-to-UART cable has some electronics built in, so they tend to be
   a bit more expensive.
</p>
<p>
   Given the extra cabling required, this connection type is a bit more work
   to set up than the USB virtual COM port optio