Facsimile
The successor in “almost-immediately obsolete contraptions” to the telex machine, nowadays the facsimile machine is mostly useful for affording bragging rights, both for those[1] who can remember having to use them and what they were for, and those who can’t[2]. the Fax was the last stand of truly analogue communication. It started out life as a piece of paper and ended up as a piece of paper. A horrid, waxy, faded piece of payment resemblent of that loo paper you get in nasty educational establishments.
Granted, there was a digital component — the document was digitised and send across a PABX network as a series of ones and zeroes — only to be undigitised and rendered full useless at the other end, the usable digital information lost forever in a squeal and whirr of odd boinky noises and static. So close, but so far away.
A fax that ran out of paper was an important McGuffin in the denouement of John Grisham's espievie thriller, The Firm. Not to be out-done, Hunter Barkley’s forthcoming novel is going to involve a malfunctioning telex.