Bell Telephone Laboratories: Quality Control
November 1947 Popular Science

November 1947 Popular Science [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Popular Science, published 1872-2021. All copyrights hereby acknowledged.

Bell Telephone Laboratories (Bell Labs) is a prime example of how a company builds a reputation as a provider of excellent products and services. Engineers, technicians, and managers designed and built a telephony system that was the envy of the world. It did so through extensive testing of designs and stringent quality control during manufacturing. The nationwide network build-out was equally robust and reliable. Constant maintenance and improvement methods developed by Bell Labs assured customers that service would be available whenever needed. Internal research in both the electronic and the mechanical arenas played a large part in their success. Being able to withstand the rigors of environmental factors (heat, cold, vibration, dirt, water, etc.) was the result of a major investment in science and engineering. Unfortunately, success went to their metaphorical corporate head and monopolistic practices caused the federal court to order a breakup of the leviathan company into small parts that needed to compete with other innovators. I'm still dubious about the decision, since Bell Telephone deserved some protection against infringement on its accomplishments. Acquiring land and building out a massive wired network could have been done concurrently with Bell's efforts, but was not. Blame for the outcome is shared by Bell and its challengers.

Bell Telephone Laboratories Ad

Your Telephone Transmitter and Receiver, voice gateways to the telephone plant, are so essential to satisfactory service that they have been under study in Bell laboratories for seven decades.

A telephone receiver is a complex system of electrical and mechanical elements. Its coils, magnets, diaphragm and cap react on each other as they convert the electrical waves of your voice to sound waves. What is the best size for the holes in the ear cap? Will 1/1000th inch greater thickness help a receiver diaphragm to carry your telephone voice more clearly? One way to find out is to build numerous experimental receivers and test them.

But Bell Telephone Laboratories have found a shorter way. They built an all-electrical replica, an "equivalent circuit" in which electrical resistance stands for air friction in the cap holes; capacitance corresponds inversely to the stiffness of the diaphragm. Over-all performance of this circuit can be quickly measured and design changes economically explored. Later, a model can be built for final check.

The "equivalent circuit" was pioneered by Bell Telephone Laboratories 25 years ago. It is a useful tool in many Laboratories developments - saving time, saving the cost of machine-tooled models, encouraging experimentation. It is one more example of the way Bell scientists get down to fundamentals as telephone progress continues-and service keeps on improving for all subscribers.

Bell Telephone Laboratories

Exploring and Inventing, Devising and Perfecting, for Continued Improvements and Economies in Telephone Service

Posted May 6, 2024