The Department of Telecommunications (ZTEL) was founded in 1951 as a unit within the University of Zagreb, Faculty of Electrical Engineering and Computing (FER). Since then it has grown and evolved to become a center for research and teaching in the areas of telecommunications and informatics. As of early 2009, ZTEL has 40 faculty, 3 staff, and about 300 students.

ZTEL is located at the 7th floor of the FER building C.

The ZTEL's main areas of research include emerging communications network architectures and technologies, and information services and software for telecommunications and IP-based networks. The ZTEL has expertise in the areas of network simulation, emulation, planing and optimisation, telecommunications software, agent and multi-agent based systems, multimedia service enablers and quality of service, interactive virtual characters and virtual humans, as well as formal methods and modeling applied to the communications and telecommunications domain.