The MMA1L10-CR module converts 4 input channels of 25 Gb/s electrical data to 4 channels of LAN WDM optical signals at 4 different wavelengths and then multiplexes these into a single optical transmit signal. Reversely, on the receiver side the module de-multiplexes a 100 Gb/s optical LAN WDM input into 4 optical signals and then converts these to 4 electrical differential output signals. MMA1L10-CR has selectable retiming as specified in the QSFP28 MSA. This enables the transceiver to be used in both 40 GbE and 100 GbE applications. Digital diagnostic monitoring functions for temperature, supply voltage and optical power are available via the two-wire Inter-Integrated Circuit (I2C) management interface, as specified by the QSFP28 MSA. The optical connector is a duplex LC/UPC (un-angled) connector intended for a pair of single mode fibers. Rigorous production testing ensures the best out-of-the-box installation experience, performance and durability.