Bell's Patent for the Telephone

Continuing with my look at historic patents, this is Alexander Graham Bell's 1876 patent (U.S. Patent No. 174,465) that was ultimately held to cover the telephone. 

The patent is titled “Improvements in Telegraphy,” and the description relates primarily to increasing the capacity and speed of telegraph signals through the use of a “vibratory or undulatory current of electricity” rather than an “intermittent or pulsatory current” as used in the prior art. The specification included only a brief reference to human voice, disclosing that electrical vibrations could be created by imparting motion to a steel-spring armature “by wind[,] by the human voice or by means of a musical instrument." Nevertheless, claim 5 was specifically directed to transmitting vocal sounds telegraphically:

The method of, and apparatus for, transmitting vocal or other sounds telegraphically, as herein described, by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound, substantially as set forth.

As we saw with Edison's light bulb patent, claims of this era included vague terms like “as herein described” and “substantially as set forth” that would not pass muster today.  Bell's claim 5 is also expressly drawn to both a method and an apparatus, which would now be deemed indefinite. See IPXL Holdings v. Amazon.com (Fed. Cir. 2005).

In his well-researched book, Invented by Law, Christopher Beauchamp recounts Bell's numerous court battles to confirm his patent's priority (over, most famously, another patent filed on the same day by Elisha Gray) and the validity of claim 5 (in view of the patent's minimal support for voice transmission). “The Telephone Cases,” as they were dubbed, culminated in an 1888 U.S. Supreme Court decision that went in Bell's favor by a single vote (4 to 3). As a result, Bell has long been credited as the inventor of the telephone.

To think, it then took nearly 100 years for someone to invent call waiting.