A telephone system is a network that allows people to communicate over distances using audio signals. It typically consists of various components, including telephones, switching equipment, and transmission lines. These systems can be analog or digital, with digital systems offering clearer sound quality and additional features like voicemail and call forwarding. Modern telephone systems can be categorized into landline and mobile systems. Landline systems use physical wires to connect calls, while mobile systems rely on cellular networks and satellites. Both types enable voice communication, but mobile systems also support text messaging and internet access, making them more versatile.