How to use an USB-attached wired Ethernet adapter through USB-OtG on an Android smartphone? Due to my profession I use to have to connect to wired-only LAN-attached devices (like managed switches, routers, set-top-boxes etc) frequently to access their configuration interfaces via Telnet/SSH/HTTP. And I am totally tired of carrying a bag with a laptop with me wherever I go.

I have just bought a Samsung Galaxy Ch@t B-5330 (Android 4.1.2) smartphone (almost the only modern model with a physical QWERTY on the market today, certainly the only QWERTY by Samsung) and an USB-OtG ("USB host") cable for it.

It would simplify my life significantly if I could connect it to wired Ethernet networks.

Is this possible? Where do I even start?

It seems to be no custom firmwares like Cyanogen Mod available for my particular model but I am most probably going to root it.

I've got a USB NIC based on ASIX AX88772 chip (which is detected by Ubuntu out of the box and is said to be compatible with XBox, PS3 and Apple Macs so it seems to be a very standard kind).

Also, I have not even found a single USB device (I have tried an USB flash drive, a keyboard and a mouse) which would work with the Android phone. It seems that they don't even receive power from it. Perhaps it (USB host mode) should be switched on somewhere in settings? I couldn't find where.
According to GSMArena, this phone doesn't support USB-OTG. That would explain why none of the other devices you've tried worked.

In that case, there's nothing you can do to make USG-OTG work, and you can't use a USB ethernet adapter.