The concept of a truly portable, handheld phone began to take shape within Motorola. Initial research and development focused on miniaturizing components and improving battery technology.

Under Cooper's leadership, a team of engineers worked to create a functional prototype of the DynaTAC 8000x. This involved significant engineering challenges related to power consumption, signal strength, and size.

Martin Cooper made the first public call using the DynaTAC prototype, proving the feasibility of the technology. The phone weighed 2.5 pounds and offered about 30 minutes of talk time.

The prototype underwent extensive testing and refinement to improve its performance and reliability. This involved addressing issues related to call quality, battery life, and durability.

After a decade of development, the DynaTAC 8000x was commercially released, marking a revolutionary step in personal communication. It cost around $3,995 at the time.