huh...
I type this into Google...
jdm programmer usb
and on the first hit, I get a standard jdm programmer circuit with a serial port at one end.
I type in usb converter, and I get lots of hits for a USB-serial converter...and get this...I also get hits for USB-serial adapter chips...like one from FTDI, a CP2102, a CP2103...
Amazing isn't it...!!!
That Google is one neato search engine ain't it?