Don't know how to use this graphical LCD


I got this graphical LCD from an old mp3 player but I don't know how to use it:

With my multimeter I can power the LED by putting the probes directly on it's terminals, also I can
power it by putting the - probe in the GND terminal of the LED and the + probe on the second pin of the board. This
makes me think that at least the second pin is VCC, but I don't manage to find GND on the board pins..
It looks like the unused pins are just for making it more stable when connected to another board inside the player.
The small number of pins makes me think that perhaps it's a serial interface, anyway, perhaps someone has used this type of screens and knows more about it, thanks! :slight_smile:

Other cross-post deleted.

Please just ask questions in the one thread.