In a mathematical sense, the curvature is the reciprocal of the radius, so that a smaller curvature implies a large radius. A curve of large radius, as for a railway, cannot be laid out by using the radius directly. We will see how the problem of laying out a curve of large radius is solved.
In 1983, Motorola released its first commercial mobile phone, known as the Motorola DynaTAC 8000X. The handset offered 30 minutes of talk-time, six hours standby, and could store 30 phone numbers. It also cost Â£2639 ($3995). In the very early days of the mobile space handsets werenât designed with consumers in mind.
On March 6, 1983 Motorola started selling DynaTAC 8000X, the first commercial portable cellular telephone, at a price of $3,995. The DynaTAC 8000X was truly the first mobile telephone which could connect to the telephone network without the assistance of a mobile operator and could be carried about by the user. It weighed 28 ounces (790 g) and was 10 inches (25 cm) high, not including its flexible rubber duck whip antenna.