Mellanox MAM1Q00A-QSA28 Ethernet Cable Adapter 100Gb/s to 25Gb/s QSFP28 to SFP28 The Mellanox QSFP28 to SFP28 adapter (QSA28) enables smooth, cost effective connections between a single lane transceiver/cable and a quad-lane port. The QSA28 provides the option to connect an SFP28 transceiver or cable to a QSFP28 port of an Nx100 Gb/s switch or network card. For example an SFP28-based cable can be connected to Mellanox’s 100GbE ConnectX-4 adapter and to the 32x100GbE SN2700 Ethernet switch.