[2][3] On April 3, 1973, he placed the first public call from a handheld portable cell phone while working at Motorola, from a Manhattan sidewalk to his counterpart at competitor Bell Labs.

Cooper left his first job at Teletype Corporation in Chicago in 1954 and joined Motorola, Inc. (Schaumburg, Illinois) as a senior development engineer in the mobile equipment group.

That original handset, called the DynaTAC 8000x (DYNamic Adaptive Total Area Coverage) weighed 2.5 pounds (1.1 kg), measured 10 inches (25 cm) long and was dubbed "the brick" or "the shoe" phone.

On April 3, 1973, Cooper and Mitchell demonstrated two working phones to the media and to passers-by prior to walking into a scheduled press conference at the New York City Hilton in midtown Manhattan.

The call connected him to a base station Motorola had installed on the roof of the Burlington House (now the AllianceBernstein Building) and into the AT&T land-line telephone system.

[15] As Cooper recalls from the experience: "I made numerous calls, including one where I crossed the street while talking to a New York radio reporter – probably one of the most dangerous things I have ever done in my life."

[6][19] Bell Labs had introduced the idea of cellular communications in 1947, but their first systems were limited to car phones which required roughly 30 pounds (12 kg) of equipment in the trunk.

In 1986 Cooper co-founded Cellular Payphone Inc. (CPPI), the parent company of GreatCall, Inc., Innovator of the Jitterbug cell phone (in partnership with Samsung).

[23] GreatCall is the first complete end-to-end value-added service provider in the cellular industry to focus on simplicity with its primary emphasis on senior citizens.

Under his leadership, the Company grew from a seed-funded startup in San Jose, California, into the world leader in smart antenna technology with 400 patents issued or pending, worldwide.

The law states that the maximum number of voice conversations or equivalent data transactions that can be conducted in all of the useful radio spectrum over a given area doubles every 30 months.