Serial acces to Raspberry Pi with RAK831 Hat adapter


For debugging purpose, I would like to access to Raspberry Pi serial terminal.
RAK Hat adapter for RAK831 - Raspberry Pi covers all the pins. There are a couple of PINs on Hat Adapter with no clear documentation. Those pins are located next to GPS Antenna connector. They have labels:

  1. GPIO15 - RXD0
  2. GPIO14 - TXD0
  3. TXD1
  4. RXD1
  • GPIO15 is connected to TXD1
  • GPIO14 is connected to RXD1

I wonder if I can use mentioned pins to access RaspberryPI serial console. If not, what would be the best way to access to Raspberry Pi Serial Console (with hat adapter and RAK831 gateway assembled)?

Raspberry Pi serial UART connection require physical access to

  • Pin 6: Ground
  • Pin 8: Tx
  • Pin 10: Rx

With best regards


While (! reply)
1 Like

Sorry to reply you so late.
Sorry to tell you again that the RAK831 serial port has been used by gps and cannot be debugged through the serial port.

Hello @barillaro
Is it possible to use USB debugging? RPi have them free. You can check here

If you describe your needs a little bit more we can try to find a solution. :slight_smile:

Todor Velev

Your best bet is probably going to be getting into the pi over Ethernet (or wifi if you ware on the same network), conventionally ssh [email protected] or whatever the settings are for the particular pi OS in use.

Another option if the system is remote is to set it up with a remote access scheme like ngrok or a DIY setup with autossh where the pi connects out to a jumphost in the cloud and creates and SSH tunnel back. This is useful if your system is on a network you can’t reach from the outside, ie, mobile carrier, home cable modem, behind firewall, etc.

To use USB you’d either need to put a USB serial converter on the target pi and have a daemon that sees that and runs a getty on that port so that you can log in there, or else use a pi0 in USB device mode similarly with a daemon to run a getty on the virtual serial device. Try asking about those on a pi-specific site, they are clever ideas but complex.

Worth noting some non-pi but pi-like boards like OrangePi’s may have sufficient compatibility of the GPIO connector and software environment to use a lot of things made for a pi, but while offering a larger number of serial ports; of course once you go non-standard you are on your own with the details of porting.

Dear ZhuQI, @velev, and @cstratton,

thank you for all your response!

I will be visiting a couple of hotels and I will need to connect my Raspberry Pi to Hotel’s network. Let’s assume that there is no captive portal on WiFi, which would make things more complex even.

My goal is to find my Raspberry Pi in a “Hotel” network to connect with SSH. As I am not the manager of the network, I wouldn’t be able to check DCHP table. Also, I can’t be sure that there is internal dns to resolve raspberry’s hostname.

@velev if I understood correctly, you suggest to connect a serial (RS-232-USB) to one of the 4 free USB-Host ports, which I would connect to similar adapter (considering male/female db-9 terminal, and null-modem connection) to my computer, right? Something like
Raspberry Pi:USB <==USB-RS232 ==x== RS-232-USB==> my-laptop
That would work, but it would be an inviable solution due to logistic restrictions.

OrangePi is not a viable solution. It would make more complex the entire situation.
NGROK option would work, if the Raspberry Pi get access to Internet.
I think ethernet cable is the best approach. :grinning:

Thank you again for your suggestions!

With best regards


Something like SSH over VPN ? Try to run some openVPN instance. I never try this but it should work.

Places like that sometimes isolate clients from each other, and it’s not a given you’d find an Ethernet jack or be able to talk to something on Ethernet from your computer on WiFi.

My recommendation would be to bring your own little router. Even if it’s unconnected to anything upstream, you could still use it to let your laptop talk to the pi by connecting both to it. (Ideally be prepared to do this all over Ethernet, as some places illegally attack “unauthorized” wifi networks by forging deauthorization packets to them - its prohibited, and they can get find by the telecom regulators but they do it anyway because it’s a checkbox in the configuration of their routers and too tempting not to click)

Or figure out how to activate internet connection sharing on your laptop, and plug your pi into your laptop as if your laptop were the router.

Another option: get a little HDMI display and bring a small keyboard.

Hi Crhis,

Thank you so much for your suggestions. Fortunately, there was no issue connecting devices to the Network. WiFi connection worked out of box, and Angry IP Scanner was able to find my device into network (beside a lot of other devices :-p)

I collect all your ideas for future deployments.

Thank you again!