A central splitter is a small passive device fitted on your wall to help reduce interference caused by your internal wiring.
If your premises have multiple phone outlets, it is recommended to install a central splitter to improve speed quality. If you choose to add it, it will be installed by an NBN technician. Labour and material charges will apply, and are not covered by standard installation. Different charges will apply depending on if you choose to install it at time of NBN installation, or later.
For fee details see FAQ: What other charges may apply?