FRITZ! ISDN-Controller C2, ISDN, 128, 14.4, 16 MB, CPU with 270 MIPS at 233 MHz FRITZ! ISDN-Controller C2. Data link protocols: ISDN. Modem speed: 128, 14.4. Minimum RAM: 16 MB, Minimum processor: CPU with 270 MIPS at 233 MHz