How to make the analog signal of telephone transmit to room B through the network port of room A switch, and then restore it to the analog signal in LAN environment?

Look at the chart. The network is a local area network connected by rj45 twisted pair, so the existing network structure lines can be used to connect fixed telephones. Because the rj45 network cable * * * has four groups of eight twisted pairs, but the current computer network only uses four of them (1 (orange), 2 (blue and white), 3 (blue and white) and 6 (green and white) (the arrangement is counted according to the crystal connection mode). Therefore, the fixed telephone can be connected with any other two wires.