Telecoms are communications networks and the companies that operate them, including systems for voice calls, text messaging, internet access, routing, and core signaling. In security work, the term covers both the public-facing services people use and the internal infrastructure that moves traffic between users, organizations, and countries.
Telecoms matter because they sit at a strategic point in the digital ecosystem. If attackers gain access, they may be able to monitor communications, disrupt service, intercept credentials, or use carrier systems as a foothold into government and enterprise networks. Espionage groups often value telecoms for quiet, persistent access rather than immediate damage. Defenders protect them with strong identity controls, segmentation, hardened administrative paths, detailed logging, and monitoring for unusual operator behavior or abnormal access to signaling and management systems.