Serial Console Access

If you're unable to access your Iron Pi using the Ethernet interface, the TTL Serial Console port can help you diagnose the issue and restore access.

The TTL Serial Console port is intended only for debugging and recovery. Use the RS-232 and RS-485 ports on the main terminal block for all serial communications in production.

The TTL Serial Console port is not RS-232 or RS-485 compatible, and connecting it to an RS-232 or RS-485 port will likely damage both the Iron Pi and the device on the other end of the connection!

The TTL Serial Console port operates at 0-3.3V voltages, and is compatible with the FTDI TTL-232R-3V3 cable, which is available from DigiKey and Amazon.

With the Iron Pi powered off, connect the cable to the Iron Pi's TTL Serial Console port. When using the TTL-232-3V3 cable, ensure that the black wire is connected to the GND pin, the green wire is connected to the rightmost NC pin, and the +5V pin on the Iron Pi is left open.

The +5V pin on the TTL Serial Console port should almost always be left unconnected

Connect the serial cable to a USB port on your computer. Allow drivers to install as needed. Open Windows Device Manager to figure out which COM port was assigned to your serial cable. In this case, our serial cable was assigned to COM4.

Install a serial terminal emulator. PuTTY is a good choice for Windows. Open your terminal emulator and connect to the serial port at a baud rate of 115200.

Power on the Iron Pi, and wait for boot messages to appear in the console. Once the Iron Pi finishes booting, you should get a login prompt. Type the username pi, and whatever password you've set for the device. If you don't remember the password, you may be able to reset it to your device's factory access code by holding down the Connect button.

Once you've logged into the device, the ifconfig -a command is a good way to check the status and IP address of your network interfaces. In this case, you can see that the device has an IP address of 192.168.100.220.

If you need to change the device's IP address, you can run sudo nano /etc/dhcpcd.conf to edit the networking configuration file.

Scroll down to the bottom to find the IP address, netmask, and DNS server settings. Once you're done editing, type Ctrl + X to save and exit.

Changes to the networking configuration file won't take effect automatically, so run sudo reboot to restart the box and apply your changes.