Terminal Emulator on Mac OS X

By | November 15, 2013

My favourite terminal program on Windows was PuTTY but unfortunately there’s no free equivalent on OS X. There’s iTerm 2, but because I need console access (serial) to configure Cisco routers, it won’t do what I need. I considered Zoc but at $80 I couldn’t justify it even though my awesome boss would reimburse me for it because it’s for work.

Serial Ports

Unfortunately my MacBook Pro didn’t come with a serial port but that’s not really strange. I can’t remember the last Windows laptop I saw with a serial port anyway. This leaves only USB to Serial converters which aren’t too hard to come by but the only ones I’ve had any luck with are based on the Prolific PL2303 chip. The one I’m using with great success is the ATEN UC232A USB to Serial Adapter.


There seemed to be two drivers available, one supplied by Prolific and the Open Source Driver I could actually get to work. If you get the Prolific driver working properly feel free to let me know in the comments section.

Making a Serial Connection

To make a serial connection on a Mac I use the screen command which works perfectly well once you add the right command line options. The basic format is something like:

$ /usr/bin/screen /dev/tty.PL2303*

That’s pretty straight forward and the only interesting thing there is the wildcard (*) on the serial port. It causes the command to connect to the serial port regardless of what USB port I plugged it into. The device name changes depending on the USB port and this way I don’t have to go looking for what it is this time.

Most of the time this just works, don’t ask me what speed it’s connecting at because if it works, I don’t really care. If it doesn’t work though, you can change the speed by specifying it on the command line. The line below will set the port speed to 115,200.

$ /usr/bin/screen /dev/tty.PL2303* 115200


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