2343988-3 is a 1x4 QSFP-DD surface mount cage connector assembly designed for high-speed 400G pluggable I/O solutions in data center and networking applications. This connector features a NET heatsink type with a heatsink height of 13.5 mm and total height of 23 mm (module inserted), optimized for thermal performance in 15-18W applications. The cage supports an eight-lane electrical interface capable of 28 Gbps NRZ or 56 Gbps PAM-4 per lane to achieve 400 Gbps aggregate throughput, with backwards compatibility allowing existing QSFP modules to be plugged into QSFP-DD ports. The connector incorporates TE's proprietary heat sink design with a specialized finish on the riding heatsink mating interface for optimal heat transfer, extensive structural analysis for mechanical durability, and wear testing to ensure reliable repeated operation. This solution is ideal for servers, switches, routers, and high-performance computing systems requiring dense, thermally efficient interconnects with superior signal integrity.