***** NOT A TEACHER *****
I went to the "books" section of Google and found that book.
1. It was published in the second decade of the twentieth century. (I am old but not that old!)
2. In those days, the telephone was the most "modern" form of communication. To the best of the knowledge, back in those days, the dial telephone did NOT exist. You had to ask an operator to connect you to your party (person with whom you wished to talk).
3. You notice that the example letter in his book uses the word 'phone. That is the abbreviation for "telephone." (In 2014, we no longer use an apostrophe. We accept phone as a word: I will phone you tomorrow.)
4. He says in his book that 'Change is his abbreviation for the word exchange.
5. And in those days, all calls went through an exchange, which one dictionary defines as "a central telephone office."
Thus, in my opinion, the sentence "Telephone us on Exchange here at our expense" would be expressed in modern American English something like: Call us collect.
P.S. I am sure that you understand that a book published in 1910, 1911, and 1914 is NOT suitable for today's business world.
Student or Learner