|Seiko RC-4000 - A wristwatch with an EIA-232 interface. A clip fitted round
the watch and made electrical contact. This clip had a socket
for a stereo style jack lead the other end of which was a
25-way D-type connector. The lead allowed you to enter
phone numbers etc. into the watch without having to play with
tiny buttons. It also meant if the battery on your watch ran
out you could restore the data without having to type it all
It was around the era of the 8-bit home computers like the Spectrum, BBC Microcomputer, Apple II, C64 - the 1980s.