The AddOn Arista Networks Compatible TAA Compliant 400G-FR4 QSFP-DD transceiver delivers exceptional high-speed connectivity for next-generation data center interconnects and high-density computing environments. This advanced module provides 400GBase-FR4 throughput at 400 Gbps over single-mode fiber for distances up to 2 km (1.24 miles). Utilizing CWDM (Coarse Wavelength Division Multiplexing) technology with four wavelengths (1271nm, 1291nm, 1311nm, 1331nm), it transmits 400G over just two fibers using a duplex LC connector, significantly reducing cabling complexity compared to parallel fiber solutions. The transceiver operates with 8x 50G PAM4 electrical and 4x 100G PAM4 optical signaling for maximum efficiency. As a TAA Compliant module manufactured in the USA or UK, it meets stringent requirements for U.S. Federal Government, military (DoD), and GSA-schedule projects where hardware origin compliance is mandatory. With typical power consumption under 12 watts and Digital Optical Monitoring (DOM) support, this module provides real-time performance tracking and network management capabilities. The compact QSFP-DD form factor maximizes port density while maintaining exceptional performance in modern data center applications requiring ultra-fast connectivity.