A 6.4Gb/s IO transceiver including an adaptive finite impulse response (FIR) filter has been implemented with 65nm technology. The FIR tap coefficients are adapted using sign-sign least mean square (LMS) algorithm. Eye-openings are improved under time varying conditions by creating a diverse channel loss environment. The transceiver consumes 64mW/lane at 1.2V supply and the chip size is 0.506 𝒎𝒎𝟐. The measured vertical eye-opening has been improved from 152.4mV/1.06V to 356.6mV/699.3mV after pre-emphasis and the measured horizontal eye-opening is 0.484 UI at 10⁻⁹ BER.