Getting Octo4a to work (or charging while being connected)

by lars on 12/01/2022

Getting Octo4a to work is actually ridiculously easy. It’s getting the phone to charge and be connected to the printer at the same time. I first tried with my old Samsung Galaxy 7 Edge, which only has micro-usb. I had to give up on that, after buying 3 different cables and even trying to charge wirelessly while connected to the printer. The wireless solution was impractical, so I gave up on that as well.

I then rummaged through my drawer again, and found the last phone I used: A Samsung Note 9 – that has usb-c so I was almost sure I would get it to work. I had an old usb-c dongle that had usb-a, hdmi and rj45 (networking). This acted very strange – I could get the phone to charge, but it would run out of juice, even when I used my beefy Samsung charger (a big one that can fast wireless charge a phone and a watch at the same time).

In desperation, and because I thought that my old dongle didn’t support PD (power delivery) over usb-c, I went and bought another cheap dongle (that specifically supported PD) and tried again. It didn’t work. But I knew it should, so I brought out a real usb-c charger (a 65 watt one, that I bought for my soldering iron, a Pinecil). IT WORKED!

Afterwards I also checked the old dongle, and that also worked.


  • Use a phone with usb-c that supports OTG
  • Enable USB debugging in android
  • Get a usb-c dongle that has usb-a and usb-c and supports PD (power delivery) over usb-c
  • Get a (high wattage) charger that has usb-c and supports PD
  • Connect the dongle to the phone, then the charger to the dongle (and verify that the phone charges) and THEN the printer to the dongle