Is there an OS X terminal program that can access serial ports?

There's a new Mac app called Serial, available in the app store. Full disclosure- I wrote it. The main advantage over other apps is it can work with most USB to serial devices without having to install any drivers, as it has its own drivers built-in. It also does full terminal emulation so you can use it to work with Linux or other devices that require it. You can try it for free, too.

Also, Apple began including their own driver for FTDI-based devices in Mavericks (10.9). So, if you're on 10.9 or later and your device has an FTDI chip inside, you can use the built-in screen command in the terminal to access your device without worrying about drivers.

You can use the terminal command screen to do this!!!

As seen on ServerFault:

I love using [screen] for connecting to serial consoles, i.e.

screen /dev/ttyS0 19200

Or, if you prefer Mac OS X hints...

I often have to do router configuration via a console port, so I use a Keyspan Serial Adapter to get access. Two problems then present themselves: ZTerm is a horrible Mac OS X app. It hasn't been updated in five years or so, and isn't a Universal Binary. The developer doesn't seem in any hurry to rectify the situation. It is not worth the shareware fee in its current form. Minicom requires installation of Fink or MacPorts and is overly complex. Solution: Use screen, Terminal, and a little AppleScripting.

First, launch Script Editor and type/paste in the following code:

tell application "Terminal"
  do script with command "screen /dev/tty.KeySerial1"
  set number of rows of window 1 to 100
  set number of columns of window 1 to 80
  set background color of window 1 to "black"
  set normal text color of window 1 to "green"
  set custom title of window 1 to "SerialOut"
end tell

Compile and save as an app from within Script Editor, and you have a double-clickable application to launch a serial Terminal session. You may want to customize this slightly -- you can change the screen colors or number of columns or rows. You may also need to customize the screen command with a different device name if you are using something other than the Keyspan Serial Adapter (do an ls tty* of the /dev/ directory to get the right name).

screen uses Control-A to take commands directed to it. So type Control-A followed by Control-\ to exit your screen session. If you fail to do this and exit a Terminal session, you'll leave the screen session alive and the serial resource unavailable until you kill the screen session manually. man screen will show you further commands to send to a screen session.

If anyone can reply with a link to a tutorial on how to wrap an interactive Unix App in Cocoa, that would be the next step -- it would be nice to do this without involving Terminal. If you prefer to use Minicom, you could still use the AppleScript to wrap it into a nice launchable app -- use this older hint to find the right command line commands.

Many USB-Serial adapters use the chip from FTDI. Install the "Virtual COM Port" driver and look for the proper TTY name in /dev. For example, on a PowerBook G4 it came up as /dev/tty.usbserial-FTALKY8I.

My preference is cu. I use it for Arduino or Bus Pirate related fun. It's installed by default and supports parity settings among other options (type man cu for more info).

sudo cu -s 115200 -l /dev/tty.usbserial-A6005kdh

To bail out when you're done, type ~. as you would with SSH

The best program I know of for this is minicom, available from Homebrew, fink, and macports.

Minicom is a serial communication program. It is a Unix clone of the well-known MS-DOS Telix program. It has ANSI color, a dialing directory, dial-a-list, and a scripting language.

Homebrew installation:

brew install minicom

If you prefer not to work in Terminal, you might mant to try CoolTerm (free). Scroll down a bit for description and download. Don’t let the fact it‘s written in RealBasic turn you away... I have used it to connect to plotters, Arduino boards and receipt printers via a Keyspan USB<->Serial Adaptor.