You need to know about the rules for investigating certain copper services. The Commission has to complete an investigation by 31 December 2025 into whether some rules should be changed. This investigation is about copper fixed line access services and some of Chorus's services. You will see that the Commission must look at things like copper fixed line access services and Chorus’s unbundled bitstream access backhaul. They also have to look at Chorus’s unbundled copper local loop network co-location and Chorus’s unbundled copper local loop network backhaul. The Commission has to follow certain rules when doing the investigation, which are set out in Part 1 of Schedule 3. The Commission must provide written reasons if they do not think there are good reasons to start the investigation. They have to do this within a reasonable time after 31 December 2025. The investigation has to be done in a certain way, as set out in Part 1 of Schedule 3, but some deadlines do not apply.