A telecommunications enclosure having a door hingedly attached to a chassis. The chassis has a first through-hole configured to have at least one patching panel installed therein. A different enclosure, like the telecommunications enclosure, is mountable on the door. The door is rotatable relative to the chassis between closed and open positions when the different enclosure is mounted thereto. The door allows access to an interior of the chassis when the door is in the open position. The chassis and/or the door may have a second through-hole configured to allow a telecommunications cable connected to the at least one patching panel to pass therethrough and exit the interior of the chassis.