The Raw Thrills cabinets have a pre-wired 3-wired dongle specifically for a MARS MEI 2600 series 12VDC Bill Acceptor. The connections are:



1.) RAW Thrills RIO Board P4  DBV_1_Blue to pin 4 on the MEI. 



2.) Power is pin 16 (Neutral) and pin 19 (Hot).