This data sheet provides detailed product specifications for an important element of the Cisco IP-over-DWDM solution, the Cisco CRS-1 4-Port 10GE Tunable WDMPHY Interface Module. This tunable DWDM interface module allows service providers to increase efficiencies, improve reliability, and reduce operational and capital costs through elimination of expensive and bulky optical transponder equipment, even as video-based applications rapidly increase traffic in their DWDM networks. The module supports both G.709 Generic Forward Error Correction (GFEC) and high-gain Enhanced Forward Error Correction (EFEC), extending reach up to 2000 kilometers (km) without requiring signal regeneration. The Cisco CRS-1 4-Port 10GE Interface Module is also completely tunable across the C band with 50-GHz spacing, and supports router-to-router SONET/SDH-like operations, administration, maintenance, and provisioning (OAM&P).