No-name i.onik android tablet not recognized by adb -- adb devices empty
Izzy’s answer is misleading. Two unrelated things were mixed up (the vendor ID list in adb on one side and the permission setup in Linux on the other side).

1) devices considered by adb:

Adb has a hard-coded list of USB vendor IDs it tries. E.g. HTC mobile phones use 0xbb4, which is listed (source file usb_vendors.c), while 0x2207 is not. 

The only way to add to this list (without patching the source) is to put vendor IDs in the file $HOME/.android/adb_usb.ini, line by line. (HOME is set up right?)

No special cable is needed.

2) permission setup for non-root access:

The udev-fiddling is to give user-access to e.g. /dev/bus/usb/002/009 (bus number/device number change; see lsusb for current values).

The details of this are not relevant to the original poster’s question, as he ran adb as root.