Networking Devices and Mac OS X

I took a Juniper Firewall + VPN Bootcamp class last week for work (it was free – usually very expensive), and I was thinking about ways to connect from my Macbook to the console port on the Juniper SSG-5 we were configuring. Well, obviously you need a USB to Serial connection, but how do you do actually connect via software.

Well, there is a way to use Terminal as a “Hyper terminal” equivalent for Mac. To do this go into Terminal. Type in “cd /dev” to get to the devices directory. Next type in “ls” to list all of the items in the directory. There will be a bunch. What you’re looking for is what beings with “cu.XXXX”. This is the USB to Serial Adapter. The name of mine is “cu.usbserial”. This name is important.

Next, even from within the same directory, type in “screen /dev/cu.XXXX” where the cu.XXXX is the name of your adapter. This will create a hyper terminal-like session that will allow you to send commands directly to the USB to serial adapter, thus allowing you to configure any device that requires a serial connection.

If you don’t want to deal with the terminal, and if you’re programming network devices where you are comfortable with the command line, there is a GUI version of a program called Quickterm. It’s available from Additionally, there is a program called Zterm. I happen to prefer ZTerm since it does allow me to use the backspace key. And since I’m not perfect, it’s very helpful.

Just thought I’d let those guys out there attempting to use a USB to serial adapter know how to connect to their gear. Let me know if there are any problems.

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