A Sidewinder is able to test 32 or 56 transceivers (depends on flavors) simultaneously. There are 32 x QSFP-DD ports at Sidewinder T400 and able to test both NRZ and PAM transceivers from 10GE up to 400GE. It integrates the functions of PRBS and Ethernet generator into one, therefore, both BER and FLR tests can be conducted.