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

in again.