Answer:
The invention of the telegraph
Step-by-step explanation:
The telegraph is an electrical device that uses coded pulses of electric current transmitted through electrical wires between the destinations. The coded pulses represent different letters of the alphabet so that complete legible messages could be sent through.
It became commercially available in the middle of the XIX century accross Europe and US. It ended in 1930's due to the invention of a more sophisticated device, the telephone.