ABSTRACT
In prehistorical years, our ancestors tied knots on a string to mark episodes of importance, so that these memorablemomentscouldberecalleda¯erward.¥isapparentlysimplemaneuverhas,infact,distinguishedhumanbeingsfromotherlivingthings,asitwasapreambleofengravedsymbolsandwritten words,theiconofcivilization.InancientChina,circa1000BCintheShangDynasty,aseriesofsmoke towersonmountainpeakswasusedtotransmitmessagestoandfrotheimperialcourt,asimpleyet eªectivelinkofcommunicationscoveringthousandsofkilometers.Itisthe¦rstdocumentedtelecommunications system in history.
