2013-06-01 · 2 min read · patrick schless

Raspberry Pi Serial Console

When setting up a new Raspberry Pi, it’s helpful to have console access, which could mean hooking up a screen and keyboard to the pi. Another option is to connect your pi to your computer with a USB cable, and connect to the serial console (similar to connecting via SSH or telnet). You need a special cable, but it saves you from having to keep a monitor and keyboard just for the pi.

The Cable You’ll need a USB-to-serial 3.3V cable. I got mine for $10 from adafruit.com.

The Setup You connect the four leads to the raspberry pi’s GPIO (general purpose I/O) pins, as shown. Red and black are power/ground, and green and white are the transmission lines. You want to avoid connecting two power sources to your raspberry pi. The normal way of powering the pi is with a micro USB port by the SD card. You should leave that disconnected, and just use the 4 leads from the USB-to-serial adapter to power the pi. If you do want to leave the pi powered by the micro USB port (maybe you want to connect to an already-running pi), just don’t connect the red lead from the USB-to-serial cable. Both setups are shown below. After connecting the 4 (or 3) leads to the pi, plug the other (USB) end into your computer.

With Power Connected Without Power from micro USB port

Software On OSX and linux, the pi will show up as a device at something like /dev/cu.PL2303-00001014 (the string after “cu.” will be different). I don’t have a Windows box, but I think it’ll show up as a COM port. To connect (again, from OSX or linux), use the command: ‘screen /dev/cu.PL2303-00001014 115200’ (replacing /dev/cu.PL2303-00001014 with whatever’s appropriate). Hit return/enter a few times, and you should be at a prompt (pi/raspberry is a likely default login/password).

Nested Screen If you run screen (or tmux) as part of your daily workflow, then you’ll find that you cannot get this to work from within an existing screen/tmux session. That’s because nesting screen doesn’t really work (and tmux is a screen work-a-like). Use the ‘screen ’ outside of screen/tmux, and you should be fine.

More information, and Windows Another great tutorial (which covers connecting via a GUI in Windows) is on adafruit.