Last night I bought a USB to Serial adapter for a project I am beginning this weekend.

It cost about $7 USD, is made by a whitebox/generic OEM, and had no detailed information on the packaging. In short, a total shot in the dark.

Luckily it uses the Prolific PL-2303, which is apparently a very popular bridge-set. Even better, it's well supported under OS X.

I downloaded and installed the drivers from Prolific, plugged it in and restarted.

Needing a way to test it, I decided the simplest way would be jack it into the console port of my Cisco switch. Now, here's how you get a console:

Open Terminal.app
Figure out the location of the USB serial port.
ls /dev/tty.*

My ouput looked like this, yours may differ:
/dev/tty.Bluetooth-Modem
/dev/tty.Bluetooth-PDA-Sync
/dev/tty.usbserial

Next I opened a screen session at 9600 baud
screen /dev/tty.usbserial 9600

I hit Enter once, and presto! I was in IOS. If you are unfamiliar with screen, you can quit by typing
Cntrl-a
Cntrl-\