Here you go.
http://www.cl.cam.ac.uk/research/dtg/attarchive/ab.htmlAs a tech journalist, I visited a chap called Andy Hopper up there in the late 80s and it was as cool as it sounded.
They also had it hooked up to their Unix box's finger command.
You could Telnet in and type Finger $username and it would return something like "Bob Smith was last seen 20 minutes ago at the ground floor lift"