Nottinghack

https://wiki.nottinghack.org.uk/wiki/Vending_Machine/Cashless_Device

Documentation Section 1 & 2 & 3 are communication protocls

Cashless device is section 7

Sparkvend Implementation

https://github.com/eltariel/sparkvend custom PI hat and teensy (with 9 bit uart support)

Vendiverse Implementation

https://web.archive.org/web/20180124042241/http://eliverse.com/content/vendiverse/

Python Implemetation (Raw MDB as far as I can tell)

https://github.com/membermatters/pymultidropbus