Martha Is Dead has a side quest called "Number 6934" (not to be missed, related to the story) that spans different chapters of the game. During this quest, you need to interact with the telegraph machine several times in order to compose and send messages in Morse code. Below is a list of all solutions for Morse code messages and the cases when they are needed.
After cutting the telephone pole wire, interact with the telegraph machine in the sheds. Here are the correct messages:
Once you have the required line of defense card, leave it next to the building next to the river.
After moving the photo under the house, interact with the telegraph machine by the barns.
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The studio has acknowledged several failures in the past.
The project is multiplayer and free.