One ancient way that cities used to communicate was to climb to a mountain and light a giant fire. There were mountains scattered all around the country, and when one went on fire, the next one would, spreading a message throughout the land.
Pigeons were used to send letters to distant places.
Runners, long distance, used to carry messages to far away places, often running for days together.
Churches and temples used to ring the bells, for people to assemble in the church or temple to get the communication.