> record a real telephone in the US and accurately capture the feeling of a long-distance call
Aside from the signalling, it would be tricky to mimic the tinny hollow sound that came on a long-distance analog connection. Sideband modulation used to reduce the bandwidth, which requires an accurate local oscillator to reconstruct, lest the voice acquire a hint of Donald Duck. Hundreds of channels each separated by a few hundred Hz of gap, all slightly bleeding into each other, the warble of modems and murmur of other speakers making noise that's not exactly white noise in the background, a propagation delay of tens of milliseconds producing an audible electronic echo/ringing, etc. Lots of people at the time would have been familiar with that sound, and it would have been hard to fake.
Aside from the signalling, it would be tricky to mimic the tinny hollow sound that came on a long-distance analog connection. Sideband modulation used to reduce the bandwidth, which requires an accurate local oscillator to reconstruct, lest the voice acquire a hint of Donald Duck. Hundreds of channels each separated by a few hundred Hz of gap, all slightly bleeding into each other, the warble of modems and murmur of other speakers making noise that's not exactly white noise in the background, a propagation delay of tens of milliseconds producing an audible electronic echo/ringing, etc. Lots of people at the time would have been familiar with that sound, and it would have been hard to fake.