Commercial Telegraph Codes

I was randomly browsing old publications online when I ran across this ad. Thinking about the topic of Communication Codes, I found it hard to believe we had never covered it at WU. But apparently not.

In telecommunication, a commercial code is a code once used to save on cablegram costs.[1]...These codes turned complete phrases into single words (commonly of five letters). These were not always genuine words; for example, codes contained "words" such as BYOXO ("Are you trying to weasel out of our deal?"), LIOUY ("Why do you not answer my question?"), BMULD ("You're a skunk!"), or AYYLU ("Not clearly coded, repeat more clearly.").

Here is a page linking to many digitized volumes.