Mac, supported usb/serial adapter but no terminal program available?

There is a neat trick in the case you have an serial adapter, but no terminal programm at your disposal, your mobile data plan don’t allow a larger download. Well, just open a shell:

screen /dev/tty.<whatever>

At least for a Sun ILOM serial mgnt port it works right out of the box. PS: Don’t use the original MacOS X driver for Prolific based USB/Serial converters, the open-source variant is a much better alternative (implements BREAK, installer doesn’t freeze) . You can download it from the sourceforge project page.