What problem has the telephone solved?

Answer 1

Before the telephone, direct communication over long distances was not very easy. There was Morse Code which some times took a long time to decode if it is something very long. There was also telegraphs which were not very convenient if it is something urgent. When the telephone was invented only the wealthy people could have them in there homes eventually middle class people had them in their homes. It wasn't until a few years later did people start to use them and Morse code and telegraphs started to go "out of Fashion". The problem that the telephone solved was the long distance direct communication thing. Now people talk to one another on the phone instead of going out, this is not very healthy. The telephone is very useful and it is good for long distance communication if we didn't have the telephone it would be very hard to talk to people directly over long distances.

Answer 2

Although this may be obvious but in the Communication Field.

Less Thought

It allows anyone anywhere to talk to anyone anywhere.

Speed

Where as before a Letter would have to be sent to the person (which could take over a week in cases country -> country) one can simply dial a number and speak immediately.

Convince

If you purely wanted to ask a simple question or needed to know something asap Letters simply do not cut the bill.

No expected length

You could call up your friend multiple times during the day with different questions, where as in a letter you would have to write the whole lot in one letter which just isn't preferred.