Complex sentence: In the twentieth century, analog telephone and cable TV networks were designed around the limitations of the technology; copper-based twisted pair networks were not able to carry TV programming, and copper-based coaxial networks were not able to carry voice telephony.
Split into simpler sentences: In the twentieth century, analog telephone and cable television networks were designed around the limitations of the prevailing technology. The copper-wired twisted pair telephone networks were not able to carry television programming, and copper-wired coaxial cable television networks were not able to carry voice telephony.