Replacing the MPO coupler panel might require that you stop all applications. Each MPO coupler panel contains three fiber coupler modules. These modules connect to the fiber cables. If only one coupler panel, it is labeled A and goes in slot 37. If two, second is labeled B and goes in slot 38, and so on. For more information about the MPO coupler panel, refer to MPO Coupler Panel in Netra Modular System Installation Guide.