DKS 1812-074 Conversion kit upgrades on older Doorking 1812 Series telephone entry system to the latest features and functionalities. It replaces the 1871-010 circuit board with the 1970-010 circuit board, upgrading the system from Classic 1812 to Access Plus 1812. The kit also replaces the black steel housing and allows for a seamless transition from the older system to the newer version.