Compromising Emanations protected Cisco 4321 Integrated Services Routers. Fibersystem routers is built around a standard Cisco 4321 Integrated Services Router, with Fiber Optical Converters added. All is enclosed in a EMC-proof enclosure to eliminate compromising emanations. At order the router is configured with optional number of 100BaseFX fiber optical interfaces, up to 16 ports. (TEMPEST/EMSEC/RÖS).