Where does cable termination occur in most buildings?
csu/dsu
core switch
demarcation point
patch panel

Demarcation Point

Explanation:

The entrance point that can  be a device for the telecommunication utilities or service providers in the building. From this device or point users of the building takes the connection to their house or building. This point is also known as the termination point of the service to the building. The purpose of the this point is to provide ease in providing their services to the users of the building. The service provider is responsible for the maintenance till this point. After this point the user is responsible for the maintenance of the cable.