US communications devices allowed in Europe?

no.

and the same is true going the other way, you cannot use EU radio equipment in the USA.

CB on 27MHz is FM and not AM

FRS is on 446MHz but that is a amateur radio band here, VHF MURS is police there.

historic ppl used drums ,smoke, marks on timber ,rocks, or the floor. Later ,fires have been used. historic Greeks used gentle beacons (fires or lamps set up on a hill, tower, or construction. ) additionally they signaled with mirrors. gentle signaling became used up into the nineteenth century,and on an identical time as previous due as WWII between ships at sea. And lighthouses have been used to warn sailors provided that historic cases. Bugle calls have been used to place across information or orders to troops provided that medieval cases. The telegraph became invented by making use of Samuel Morse interior the mid nineteenth century,because of the fact the 1st digital means of verbal exchange. THen telephone, radio, fax, television and computers developed particularly immediately interior the subsequent one hundred years.

Absolutely not! Frequencies and modes are totally different.