"Telephones have become de facto communication devices..."
Really, I didn't know the telephone was invented for any other purpose than communication. Trevor, you're the second best writer at the TD, but please purchase a dictionary.
The use of de facto in this case means existing without recognition.
In essence, what he seems to be saying is the telephone / landline is there (existing) but more people are using their cell phone and ignoring (without recognition)the landline.
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