There are some legacy systems that security newbs should know how to handle simply because they just work. These systems have been around and deployed long before those who are fresh out of school and entering the security industry were born, the newbs still need to understand and watch these legacy systems. Fax machines are still very widely used for many business transactions, including health and finance, while being incredibly insecure both digitally and physically. Modems can allow a form of access into a computer that is otherwise protected by firewalls and all other technologies to make sure no one gets into your network.”]
Source: https://www.csoonline.com/article/3095711/legacy-systems-that-security-newbs-need-to-watch.html