Telecommunications is the transmission of any type of signals for the purpose of communicating. It can include connections with phones, cables, fiber-optics, satellites, and much more. Data transmitted over any of these connections faces certain risks, such as the risk of capture. For example, an attacker can use a sniffer to capture traffic going over the Internet and view and analyze all the data.
A significant amount of telecommunications traffic goes over the Internet. This includes typical Internet traffic such as web pages and e-mail, streaming audio and video, and some types of voice communications. However, phones have not been replaced and still have some risks worth exploring.