Last modified: December 31 1969 16:00:00
The RS-232 serial port on network switches and routers (and other devices) remains a staple even on modern equipment; if you've just hosed yourself out of the router with a bad config edit and you can't telnet back in, the console port is your only hope.
But, in this day and age, all Macs and most if not all PCs come with NO serial port anymore; and there are zillions of USB adapters, but some are only for PDAs, and others need drivers that aren't supported anymore, or conflict with something else, or whatever...and then, even if you've got the hardware all set to go, how do you actually make the connection? And even if you figure that out, what if you've got a Mac?
This is one of those things which is so basic that it's almost impossible to find out how to do it, because no one's written it down, because everyone already knows how. Or something. Whatever the case, I had a hell of a time figuring it out. So here's a quick-n-dirty recipe for doing it on a Mac (in this case, a newish Intel-based MacBook). This is just one viable combination of hardware and software, that worked for me.
and reboot as prompted.
screen /dev/tty.PL2303-0000101D 9600
When you're finished with your session, log out, then unplug the USB cable from your Mac. This will terminate the screen session. It will also trigger a warning about removing the USB device while an application is still active; you can safely ignore that.
One alternative to Terminal/screen is the ZTerm program. Make sure that the USB adapter is plugged in before you launch ZTerm, or it won't be listed as a possible port. Hold down Shift while launching ZTerm and select whichever port has "PL2303" in the name.