To obtain a wiring system in which existing communication units, e.g. telephones, facsimiles, and the like, connected with other telephone outlets through an existing wiring can be used while utilizing Internet connection service through a public telephone network.

The wiring system comprises a first communication path 1 wired in a building H, a plurality of main telephone outlets 21-23 provided on the first communication path 1 in the building H, a second communication path 3 wired in the building H, a sub-telephone outlet 4 provided on the second communication path 3 in the building H, a switching connector 5 for connecting a subscriber line 20 of a public telephone network with the first communication path 1 or the second communication path 3 while switching alternatively, and a panel 6 disposed in the building H and containing at least one main telephone outlet 21, the sub-telephone outlet 4 and the switching connector 5.