How does energy transform in a telephone?

Question

(Transformation of Energy in a Telephone)

Answer 1

in a telephone the sound energy is converted into electric pulse voltage by a microphone....these pulse waves are transported ...then these voltage pulses are again converted into sound at receivers end

Answer 2

Vibrational (mechanical) energy of the sound waves --> potential difference energy(electrical -a.c) to the next phone and the same process is repeated backwards