What's the AC meaning there, see the bellow snapshot.
I don't know why they use the AC label. It is an OLT (Optical Line Termination). The OLT provides two main functions:
Performs conversion between the electrical signals used by the service provider's equipment and the fiber optic signals used by the passive optical network.
Coordinates the multiplexing between the conversion devices on the other end of that network (called either optical network terminals or optical network units).