what does "ticker"mean?
By now three bulletins had arrived. All the men were present, and Rusk said quietly, "We have just received a ticker report, which may or may not be accurate, that the President has been shot in Dallas, possibly fatally."

A ticker was a sort of teletype, or punch printer. It was used to relay messages, a bit like a telex. It may have even been a name for a telex. 
It was slightly more automated technology than Morse code!