For the picture, look here:
This is the keyboard i now use.
It worked out of the box (!): by connecting the dongle to the OTG cable.
Ideally, the dongle would be replaced by an App, using the Fonepad WIFi.
Ideal would be to have this keyboard with Bluetooth… (Less radio-toxic).
The Keyboard cobtains a track-ball mouse and mouse buttons below that as well as on the corners of the keypad.
Also, media control and navigation buttons are available in thumb-range.
A clever device.