Real time, text communications are not the invention of email. In the 1960’s and 1970’s, long distance was expensive and fax very slow. Vulcan needed an alternate method to communicate in real time for the following reasons: Telex was the obvious answer.
https://vulcanhammer.info/2017/07/14/a-few-words-about-the-telex/
https://vulcanhammer.info/2017/07/14/a-few-words-about-the-telex/