That's right. The internet signals are treated the same as the TV signals- and amplified periodically as they travel down the cable to compensate for attenuation. This is the way cable-TV has always worked so adding internet didn't require major changes in plant design- only replacing one-ways amps with bi-directional amps to handle the upstream. But phones systems were designed to handle only low-freq audio frequencies so adapting them carry digital data especially at high speeds has been a problem. In areas where phones systems are being completely rebuilt it is more along the lines of cable-TV systems with the audio is converted to a digital stream and combined into one pipeline. Someday phone and TV will merge into one system but it will take a long time to replaced the infrastructure thats in place now.