A device with a Type-C connector does not necessarily implement USB, USB Power Delivery, or any Alternate Mode: the Type-C connector is common to several technologies while mandating only a few of them.
I asked this soon after the FP3 launch, and more recently asked @Monica.Ciovica in another thread with other questions about specifications. But so far we don’t have a clear answer (same as we don’t have a clear answer on other things like Bluetooth, NFC, etc). I think the only way we will know is by people doing tests.
BTW, this problem of unclear specs is not limited to Fairphone, it seems to be the case with most or maybe all modern smartphones. Gone are the days where the specs list was a full page in small print listing every possible feature, most OEMs now just seem to list the highlights, probably to hide the fact they haven’t properly tested everything else.
Again, this is another way that Fairphone could stand above the rest, if they are able to.
I guess, that’s the problem, even for the global players.
To test all possibilities in all kinds of environements (i.e. with all kinds of apps or combinations of apps) seems rather complicated. Especially if you want to guarantee, that a certain feature is working.
Actually it’s not complicated at all. All of the standards bodies (Bluetooth SIG, USB Implementers’ Forum, NFC Forum, Wifi Alliance, etc) have test suites which can and should be used by the OEM to confirm compatibility. Some standards, e.g. Wifi and Bluetooth have specific certification which needs to be obtained before they can be marketed as having those features, but that doesn’t appear to be the case for USB and NFC. The wireless certification may also be required by national certification for RF communication, e.g. EU RED and FCC, etc.
So, it’s not difficult. But it does often require paying a dedicated laboratory to do the tests, so maybe that is the problem. However, I can’t believe that Fairphone would bring a phone to market without actually testing USB and NFC…
OTG works, I connected mouse and keyboard via a USB hub. I also were able to access a microSD card via a USB adapter.
I haven’t tried to connect a monitor yet, but I do not expect it to work.
Fairphone 3 uses USB 2 with a type C plug as far as I know.
This is because of the OTG protocol. Micro-USB plugs have a fifth pin to enable/disable OTG. In a normal cable this pin is not connected, in an OTG cable it is connected to the ground (the metal shell of the plug.)
USB-C has a different protocol in which devices can negotiate which one is host, so in a ‘normal’ USB-C to micro-USB converter, the pins will likely not be connected to each other and the phone will not notice that there is an OTG device attached.
This forum-thread is a nice overview of the capabilities of the usb-c connector in the FairPhone3. For everyone using the list, keep in mind that the FairPhone can run multiple different operating systeems. And some of the usb-features are also software-depentent. Hence, if the OS is not mentioned, expect it to be for Android, in the ‘current’ version at the time of writing: in 2019/2020 this is Android 9.