The rise and fall of videophony (pp. 150–151)
And of course but these advantages were nothing other than the once-lost and now-appreciated advantages of good old Bell-era blind aural-only telephoning, with its 6 and (62) pinholes. […] In other words a return to aural-only telephony became, at the closed curve's end, a kind of status-symbol of anti-vanity, such that only callers utterly lacking in self-awareness continued to use videophony and Tableaux, to say nothing of masks […]
Context
The videophony curve actually closing: consumers arrive back precisely where they started, with the old phone's blindness now a luxury feature. "At the closed curve's end" — the essay names the completed circuit as it completes.