OK, I discovered the problem/solution. It was a bit of a jigsaw. The thing is: there are different variants of the joyadapter.
And there is an error in the text of mr. Levente, who gives a design of the Joyadapter.
My off fabric Joyadapter did not work together with a bought, homebrew joyadapter.
If you want the Unijoysticle 2 with DB9 connectors to work on a C16/+4 together with Joyadapters, you have to be sure that the adapter has:
Pin 5 (+5VDC) minidin NC
Pin 7 (GND) minidin NC
USB external PSU
The error in the text of Mr. Levente is the statement that pin 7 minidin must be connected to pin 8 DB9, but: pin 8 (Minidin, data/select) must be connected with pin 8 (DB9, GND). I already correspond wit Mr. Levente, he confirmed the error in the text. I hope he wil adjust the text, while it could be pretty destructive for the TED latch.
However, there is a brandnew C16/+4 adapter been developed, with direct Minidin connection on C16/+4 and more safe electronics.