Telco Cores EN CN Telco cores are IP cores, which are specific for telecommunication and networking applications. OTL4: 100G Digital Core This IP provides OTL4 layer function to OTU4 or OTUCn. SF-S: 100G Digital Core This IP provides 100G/s Constant Bit Rate (CBR) connectivity between ASICs/FPGAs. SF-5: 40-50G Digital Core This IP provides 40-50G/s interface used in OTU3 or similar application. SONET/SDH: OC192/STM-64 Framer This is a SONET/SDH framer at 10G/s. SONET/SDH: OC 48/STM-16 Framer This is a SONET/SDH framer at 2.5G/s. SONET/SDH: OC12/4xOC3|STM-4/4xSTM-1 Framer This is a single SONET/SDH framer at 622M/s or quad-OC3/STM-1 framer.