DSP-based transceivers above 100Gb/s have demonstrated the ability to handle up to 38dB insertion loss (IL) with low-to-moderate crosstalk –[2]. At same time, power scaling techniques [3] have closed the energy efficiency gap compared with analog/mixed-signal transceivers on shorter links. Notwithstanding advances in materials and connectors, in large repeater-less backplanes, transceivers are required to operate reliably at 100Gb/s with more than 40dB IL. Furthermore, next generation computing and AI applications require 50Gb/s rates per lane on channels with more than 45dB loss but without the latency of forward error correction (FEC). In this paper we demonstrate a reconfigurable ADC-DSP SerDes capable of operating with BER $\le 1E-05$ at 112Gb/s in PAM-4 or Duo-PAM-4 across a 45dB loss channel, and 58Gb/s PAM-2 at $\lt 1E-15$ over a 52dB loss channel without FEC, while achieving a power efficiency better than 6pJ/b. The SerDes architecture is shown in Fig. 8.4.1 and features extensive power scaling capability.