From Unofficial Stationeers Wiki
Using Access Controller cartridge in Tablet player can assign or restrict access to object tablet points at. Access will be granted based on various colors of access cards. In order to be able to interact with secured object, a player must have in their possession an access card of the matching color. Access cards must be in either hand, or in the Access Card slot in uniform (Uniform Comander can hold two).
First appeared in patch v0.1.1362.6552