The Vendo Univendor was capable of logic and MDB interface. The MDB interface does not alwasy interface with card readers. A module kit may be needed to add a cashless device such as a card reader. 

Your machine must have the 12 position changer socket in order for this kit to work.

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.