I am especially interested in Bell, the breaking up of Bell, The Baby Bell's, IBM, Dell, the Tyson's Corner Virginia area's rise as a tech hub, as well as the History of Tech in Austin Tx, Dallas, TX, Seattle, Washington, and perhaps San Francisco, but I feel most of that has bee in the last 20 years.
You could fill a library, but if you want to read about the actual technology involved in the Bell System I'd suggest the seven volume series called A History of Engineering and Science in the Bell System. It was published in the late 70s / early 80s by AT&T and Bell Labs and covers pretty much everything the Bell System did between 1875 and the early 1980s. It's not the easiest set of books to find. Most major libraries should have them though and most university libraries as well.