[Jethomson] worked out a way to use a Nokia USB cable at a USB to Serial cable. He was able to pick up one of these cables for less than $3 delivered. A little probing worked out which conductors ...

The classic serial null-modem cable was, among other things ... [Nick Sayer] needed just such a tool, but one that would work in a modern USB environment. Enter the isolated USB null-modem.