This is the “final” version that Dragino sent to us on October 2017
The “first prototype”:/article/first-prototype-is-out-of-the-factory/ is based on this Schematic
(The first draft of the Schematic was done back in April, which was internally circulated, revised, and modified, and after at least 4 such iterations, this final document was approved and used to produce the first prototype)