What is the 'microcontroler' setting under 'networks?

Question

I was looking through the network settings on my 2015MBP and I came across this.

What is the microcontroler? It looks like it can be used to make telephone calls from the Mac as shown here

What is this, how does it work and how do you set it up?

Thanks

Edit

Here is the output from the commands that Rogiersuggested

network services output

(1) Microcontroller
(Hardware Port: Modem (usbmodem1422), Device: usbmodem1422)

(2) Bluetooth DUN
(Hardware Port: Bluetooth DUN, Device: Bluetooth-Modem)

(3) Wi-Fi
(Hardware Port: Wi-Fi, Device: en0)

(4) Bluetooth PAN
(Hardware Port: Bluetooth PAN, Device: en3)

(5) Thunderbolt Bridge
(Hardware Port: Thunderbolt Bridge, Device: bridge0)

Hardware Ports output

Hardware Port: Wi-Fi
Device: en0
Ethernet Address: 00:00:00:00:00:00

Hardware Port: Bluetooth PAN
Device: en3
Ethernet Address: 00:00:00:00:00:00

Hardware Port: Thunderbolt 1
Device: en1
Ethernet Address: 00:00:00:00:00:00

Hardware Port: Thunderbolt 2
Device: en2
Ethernet Address: 00:00:00:00:00:00

Hardware Port: Thunderbolt Bridge
Device: bridge0
Ethernet Address: N/A

VLAN Configurations
===================

Note:
I have changed the MAC addresses to 00:00:00:00:00:00 for security reasons since they can be spoofed.

If it helps I remembered I created an Wi-Fi hotspot on my Mac by clicking on the Wi-Fi menu and clicking on create network

The 'grep' command did not display anything. (used usbmodem1422 as the argument.

Answer 1

The icon indicates its probably a serial device (i.e. a virtual com port).

Normally you need to click the + sign below (your first screenshot), then select a interface, a default name will be presented (in your case Microcontroller). You could rename the service afterwards.

The problem is once the device is added its hard to see which port its connected to. Now if you goto the Terminal and type:

# list all h/w ports
networksetup -listallhardwareports

# list Services and their connected port
networksetup -listnetworkserviceorder

The last command should show you something like:

(1) Ethernet 1
(Hardware Port: Ethernet 1, Device: en0)

(2) Ethernet 2
(Hardware Port: Ethernet 2, Device: en1)

(x) Microcontroller
(Hardware Port: xxxx, Device: YYYY)

The device name (YYYY) you should find in your /etc folder (if connected).

So, if the device is connected you should find it in that /dev folder. You can check this by going to the terminal and type:

ls -l /dev | grep <the name of the h/w port>

If you then disconnect the device and they the command (above) again, and it disappears your sure.

To answer your question: how it works and how you set it up depends on what type of device it is. And its hard to say just based on this information.

Apparently this device got somehow added. As Ashely states, it could be a Raspberry PI, or some other USB device (with serial port).

Answer 2

I have an Arduino (which has a "microcontroller" processor). I'm no expert on "modern" devices (like this, and Raspberry Pi etc), but I have worked with older similar systems.

On my system, the Arduino instructions suggested I installed the CodeBender development software to work with the device. That insisted on installing driver-installer.mpkg, which seems to contain FTDIUSBSerialDriver.kext, which seems to implement /dev/cu.usbmodemfa121 and a setting in System Preferences > Network similar to that in your screenshot. Sadly I couldn't find any documentation from CodeBender explaining this: I had to look closely at the installation package to work this out.

On my Arduino, I believe the microcontroller has a USB wrapper around a virtual RS232 port. It's used to send compiled code to the Arduino from the development software on the Mac, and in the other direction for the Arduino to send output back to the Mac.

In the comments, you say that the main Raspberry Pi USB port doesn't have data connections. But perhaps the development software has installed this network/USB/RS232 port anyway. It appears on my Mac even when the Arduino is not connected.