The QSFP-40G-eSR4 transceiver is a Quad Small Formfactor Pluggable module for bi-directional serial optical data communications such as 40GBASE Ethernet and 10GBASE Ethernet. The transceiver uses four parallel data streams of 10.3 Gbps to provide an aggregate signal rate of 41.2 Gbps. The module has an MPO12 male connector and uses four fiber pairs to create the four data lanes.

The modules are fully compliant to the QSFP+ MSA SFF-8436 and are hot pluggable. Digital diagnostic functions are available via an I2C serial bus also specified in SFF-8436. The modules meet the requirements of the IEEE 802.3 40GBASE-SR and are suitable for interconnections in 40G Ethernet environments.