This for all those folks who want to know how to connect to a console port on a Cisco device (or any console, really) using a Mac. Because OSX is built on a Unix derivative, it includes a number of tools that are built in, including a little application called screen. You don’t need SecureCRT, Putty, or any other application. Screen is a powerful application with a number of different uses, but the manual page is as cumbersome as any. Using it to connect to a Cisco device, however, is easy. You only need to take three steps to use it successfully.
First, connect your Mac to the console port using any Mac compatible USB/serial adapter.
Second, from the terminal, run the ls /dev/tty.* command. This will show you the name of the USB/serial adapter as it appears in the /dev directory.
Third, from the terminal, run the screen /dev/tty.<device name> 9600,-cstop,-cs8,-parenb command. This invokes Screen using the USB/serial adapter, instructs it to use 9600 baud, one stop bit, 8 data bits, no parity.
That’s it. When you are finished, press and hold the <control> <a> key combination and then press the <d> key. This will disconnect screen and release the terminal. If you want to know more about how Screen works and all that it can do, read the man page.