The Vendo Univendor was capable of logic and MDB interface. The MDB interface does not interface with card readers. A module kit is needed to add a cashless device such as a card reader as the board’s software is too old and was never updated by the manufacturer. 

When an MDB update module kit is installed, and if the changer and validator are not currently MDB, they will need to be replaced if you wish to accept coins and bills. If you will be cashless only, the changer and validator are not needed. The plug on all MDB devices is a 6-position connector arranged 2 x 3.