The first published mention of the idea was in 1888, in the American
journal "Electrical World".  One year later a Danish inventor, Valdemar
Poulsen, began development of audio recorders using steel wire and tape
and, at the Paris International Exhibition in 1900, he demonstrated
what we now call the "telephone answering machine" !

In 1925 the Vox company of Germany marketed the Dailygraph, an improved
wire recorder for telephone messages and dictation.

The USA didn't show interest until 1930, when Bell Telephone
Laboratories initiated "a major research effort in magnetic tape
recording under the direction of Clarence N. Hickman."  Prototype
recorders were built using steel tape, but no products entered
successful production.

Read more about it (including singer Bing Crosby) at the web page,
"History of Magnetic Recording",

  http://www.ozemail.com.au/~bassboy/getreel/history.htm

Robbie Rhodes