The Cisco DWDM-SFP-3504Â 1000BASE-ZX Ethernet transceiver is a DWDM SFP transceiver for optical communications, rated for distances up to 80 km and a maximum bandwidth of 1Gbps. The DWDM-SFP-3504Â transceiver operates at 100GHz (C-Band) wavelength. 1000BASE-DWDM 1535.04 nm SFP (100-GHz ITU grid). The Cisco Dense Wavelength-Division Multiplexing (DWDM) Small Form Factor Pluggable (SFP) module allow enterprise companies and service providers to provide scalable and easy-to-deploy Gigabit Ethernet or Fibre Channel services in their networks.