A telecommunications apparatus comprising: a terminal housing defining an enclosed interior and an exterior, the terminal housing including at least one exterior module mounting location including a first mechanical connection interface; and an add-on module (630a, 630b) adapted to be integrated with the terminal housing at the exterior module mounting location, the add-on module (630a, 630b) including a module housing (632a, 632b) carrying a second mechanical connection interface that interlocks with the first mechanical connection interface to fix the module housing (632a, 632b) in place relative to the terminal housing, the first and second mechanical connection interfaces (608, 634) being configured such that the first and second mechanical interfaces (608, 634) can be interlocked without requiring the terminal housing to be disassembled, the module housing (632a, 632b) including at least one exterior connector port for receiving an exterior fiber optic connector, the exterior connector port being capable of receiving the exterior fiber optic connector from outside the module housing (632a, 632b) and the terminal housing when the add-on module (630a, 630b) is integrated with the terminal housing, the add-on module (630a, 630b) also including an optical connection structure for providing an optical connection between at least one optical fiber of the terminal housing and the at least one exterior connector port; wherein the terminal housing forms a main terminal that is substantially larger in volume than the add-on module (630a, 630b), wherein the main terminal is configured to receive a pass-through cable, wherein optical fibers of the pass-through cable are accessed within the main terminal, and wherein the main terminal houses one or more splice trays. a terminal housing defining an enclosed interior and an exterior, the terminal housing including at least one exterior module mounting location including a first mechanical connection interface; and an add-on module (630a, 630b) adapted to be integrated with the terminal housing at the exterior module mounting location, the add-on module (630a, 630b) including a module housing (632a, 632b) carrying a second mechanical connection interface that interlocks with the first mechanical connection interface to fix the module housing (632a, 632b) in place relative to the terminal housing, the first and second mechanical connection interfaces (608, 634) being configured such that the first and second mechanical interfaces (608, 634) can be interlocked without requiring the terminal housing to be disassembled, the module housing (632a, 632b) including at least one exterior connector port for receiving an exterior fiber optic connector, the exterior connector port being capable of receiving the exterior fiber optic connector from outside the module housing (632a, 632b) and the terminal housing when the add-on module (630a, 630b) is integrated with the terminal housing, the add-on module (630a, 630b) also including an optical connection structure for providing an optical connection between at least one optical fiber of the terminal housing and the at least one exterior connector port; wherein the terminal housing forms a main terminal that is substantially larger in volume than the add-on module (630a, 630b), wherein the main terminal is configured to receive a pass-through cable, wherein optical fibers of the pass-through cable are accessed within the main terminal, and wherein the main terminal houses one or more splice trays.