Osx Usb Serial Terminal
Mike s PBX Cookbook
Mac s and serial TTY s
Mac s are excellent tools for accessing serial device TTY ports to console into PBX s, switches, and routers. You just need a serial to USB adapter, the right driver, and some Terminal software.
You can use screen, although Minicom or a GUI program offer more features and functionality.
Drivers:
Most Serial-to-USB adapters will work on a Mac with one of the following OS X drivers
UPDATE: Mavericks 10.9 includes a driver for FTDI-based Serial-to-USB adapters.
Prolific PL2303:
If your adapter doesn t work with either of these, try the following sources:
Silicon Labs - CP210x USB to UART Bridge Virtual COM Port VCP drivers.
Belkin - USB Serial Adapters: F5U257, F5U103, F5U003 poor OS X support.
Keyspan serial-USB adapter drivers can be found in their Support Section.
NOTE: It may be necessary to remove any previous driver before installing a newer one,
eg: sudo rm -rf /System/Library/Extensions/ProlificUsbSerial.kext
After installing the correct driver, plug in your USB-Serial adapter, and open a Terminal session Applications/Utilities.
Enter the command ls /dev/cu., and look for something like usbserial or similar :
ls /dev/cu. /dev/cu.Bluetooth-Modem /dev/cu.iPhone-WirelessiAP /dev/cu.Bluetooth-PDA-Sync /dev/cu.usbserial
This indicates the USB-Serial driver is working. Select this port name in a terminal program.
Note: Check your USB adapter works after a Mac OS Update, as you may have to re-install the driver.
You might notice that each serial device shows up twice in /dev, once as a tty. and once as a cu.. So, what s the difference. Well, TTY devices are for calling into UNIX systems, whereas CU Call-Up devices are for calling out from them eg, modems. We want to call-out from our Mac, so /dev/cu. is the correct device to use.
The technical difference is that /dev/tty. devices will wait or listen for DCD data-carrier-detect, eg, someone calling in, before responding. /dev/cu. devices do not assert DCD, so they will always connect respond or succeed immediately.
Software:
Having installed the right driver, our USB-Serial adapter will show up in /dev/cu. shown above. We now need to install some terminal emulation software before we can connect to anything.
Two terminal methods are Screen and Minicom
For a GUI solution, see OS X Serial Port Apps
Note: If you can t find a driver for your adapter eg, Belkin, try Serial which has built-in support for many USB-Serial devices.
Screen
It s not actually necessary to download an install extra software, as you can use the Mac OS X built in Terminal and screen. Screen lacks some features, but it does include VT100/ANSI terminal emulation, and can be extremely useful.
Open an OS X terminal session window
Find the right TTY device. Type: ls /dev/cu.
With the USB-Serial adapter plugged in, you ll get a list, including something like this:
Then type: screen /dev/cu.usbserial 9600 in this example.
The 9600 at the end is the baud rate. You can use any standard rate,
eg, 9600, or 19200 for a Sig Server.
To quit the screen app, type CTRL-A, then CTRL-.
Type man screen in Terminal for further information on screen. use enter or space to scroll, and q to quit.
Minicom
Alternatively, if you d like a few more features, and a retro feel, you can install minicom 2.2
.
Minicom supports VT100 emulation, which means it sorta kinda works with Meridian Mail Function keys: fn f-key.
Download and run the minicom 2.2 package installer.
Then manually edit your PATH with sudo nano /private/etc/paths.
Add the following line to the bottom of the file: /opt/minicom/2.2/bin, save and exit - then relaunch the terminal.
Run minicom -s first to configure your serial interface device name, and other options. Then, Save setup as dfl default and Exit. Your serial interface device name is found with ls /dev/cu. as shown above. Always launch minicom, with your selected serial adapter plugged in and available to avoid an error. In the example below, the serial device is /dev/cu.usbserial:
Configuration Options
Connected to Port
Command Summary
In minicom, commands can be called by CTRL-A, for example, change your serial port settings with CTRL-A P
Press CTRL-A Z for a Command Summary, and help on special keys. Enter CTRL-A X to quit.
HINT: Change your OS X terminal window size to 80x25 1 line more so you can see the bottom Minicom status bar.
Terminal Preferences - Settings - Window. Open a new window for this change to take effect.
Note, the minicom installer creates /opt, and its not hidden in the OS X finder. Rectify this with: sudo chflags hidden /opt
Connecting
With handshaking set to software xon/xoff or none, which covers most devices, serial data communication needs just 3 wires: RXD 2, TXD 3, and GND 5. Generally, hitting should cause a response, or should re-draw the screen. If you don t get any characters, try adding a Null-Modem cable or adapter, which swaps RXD and TXD pins 2 and 3. Pin 5 is ground.
Pin Functions for RS-232.
Here s how to read and send serial data from the terminal in OSX. Serial Console on OSX. I bought a USB Serial port that had MAC drivers.
Just for the records, i could successfully install the driver and use the USB-Serial adapter on Mac OS v10.8.2 Mountain Lion. The only difference from the tutorial.
Setting up a Serial Console in Mac OS X. One of two things is generally meant by this, either using a Mac as the interface to a serial device accomplished by running.
This describes how to get a terminal window on a Mac to a USB device or a serial device connected using a USB-to-Serial adapter in this case, a Keyspan USB High.
What programs can act as a terminal and access serial ports. This is not for terminal access on an IP connection, this is so I can access a hardware device plugged.
