.Radio

Until  the  mid-1800s,  communicating  over  distances  meant  waiting  long  periods  of  time  between  transmission  and  reception.  Visual  signal  systems  such  as  the  semaphore  (a  system  using  torches  or  flags  to  convey  meaning)  used  by  the  Romans1  and  the  French2  and  smoke signals used by Native Americans were rapid, but  the  amount  of  information  that  could  be  transmitted  quickly and effectively was limited.