The following lecture notes are available for download in book form:
Digitale Bildcodierung (4MB)
Digitale Kommunikationstechnik (6MB)
Foundations and Applications of Cryptology (3MB)
Graphen, Algorithmen und Netze (4MB)
Internet Techniques (3MB)
Kommunikationsnetze und -protokolle (8MB)
Network Security (10MB)