noun
public network
Technical computing term for a network accessible to the general public, as opposed to a private or closed network.
公衆回線網を利用してインターネットに接続する。
Connect to the Internet using a public network.
専用線 is a dedicated or leased line, while 公衆回線網 is a shared public network.
Compound of 公衆 (public) + 回線 (circuit/line) + 網 (network).