Britannica Educational Publishing 
Breakthroughs in Telephone Technology [PDF ebook] 

In an age where near-instantaneous communication is available through all manners of portable and pocket-sized devices, it is easy to overlook the genesis of telecommunication instrumentation-the telephone. Since Alexander Graham Bell patented the first phone in the 1800s, the telephone has undergone numerous changes to its look and functionality. This detailed volume examines the development of the telephone and related technologies, including everything from the transistor to fax machines, smart phones, and Vo IP technology.