The main hardware for dispense consists of a CokeMachine and a SnackMachine. Both of these machines are connected over serial to a Debian box which runs the software (Merlo). Please see their individual pages for further info.
Merlo runs two deamons; one written in python for the SnackMachine (the vendserver component of dispense2), and one written in c which does all the banking and controls the CokeMachine (OpenDispense2).
Merlo also controls the UCC door. The door solenoid (ie the lock) is connected to the on-hook relay of a modem, which is mounted on the wall in the machine room. This modem is connected via serial to Merlo.