Combining the two techniques should allow the telephone signal to be read as far as a few hundred kilometers without a relay, which basically lets it cover most of the residential areas in the Western Region, and would allow Neverwinter to receive real-time updates from the defensive line in the Impassable Mountain Range.
If he wanted to further extend the range, he would then have to use a signal relay.
The reason why Roland chose to develop the wire telephone was not only because he was inspired by Anna's words, but also because of the vast usage and practicability of this tool. It would serve as a crucial piece for controlling the political situation, enhancing the centralization of the government, and commanding the wartime efforts.
More importantly, the industrial projects in Neverwinter had already reached a saturation point.