The old Bell System used to advertise extensively in magazines. Some of the magazines are now available on Google Books. Here is how to search for them from LIFE Magazine.
1) Use the URL2) In the search string, enter LIFE Bell Telephone.
3) Under TOOLS, select MAGAZINES. (This will eliminate books).4) This will display various issues. If you click on a reference, it will display the ad (or an article).
5) Some experimentation may be necessary.You should vary the search string, such as "LIFE WESTERN ELECTRIC". To get old Western Union ads, enter "LIFE WESTERN UNION" (no quotes).
Bell also advertised in other publications. For a while they advertised in BOYS LIFE. Simply say "BOYS LIFE Bell Telephone" to bring up those references.
In LIFE, Bell advertised roughly every other week. During WW II, Bell asked customers NOT to use the telephone and be patient due to war traffic, as well as touting their contributions to the war effort. After the war they asked for patience while they caught up on a huge backlog of service orders. In the 1950s, they touted their contributions to the Korean War and Cold War defense. By the later 1950s, Bell had caught up to consumer demand was now advertising long distance and extension phones.
Bell sometimes advertised in Billboard magazine. These ads were mostly geared toward the television industry.