Kadamba script

The Kadamba script is the first writing system devised specifically for writing Kannada and Telugu. It is a descendant of the Brahmi script. The Kadamba script is also known as "Pre-Old-Kannada script". This script later became popular in what is today the state of Goa and was used to write Kannada and Sanskrit.
The Kadamba script is one of the oldest of the southern group of Brahmic scripts that evolved from the Brahmi script. By 5th century CE it became different from other Brahmi variants and was used in southern Indian states of Karnataka and Andhra Pradesh. It evolved into the Old Kannada script by the 10th century CE and was used to write Kannada and Telugu. It is also related to the Sinhala script.
History.
During the rule of Kadamba dynasty (325-550), major change in the Brahmi script resulted in the Kadamba Kannada script, letters were shorter and round in shape. During (325 to 1000 AD) the rule of the Western Ganga dynasty in the southern parts of Karnataka the Kannada script used differently (also known as Ganga script) in rock edicts and copper plate inscriptions. 
During 6th to 10th century, the Telugu-Kannada alphabet stabilized during the rule of the Chalukyas of Badami from 500-1000 and Rastrakutas.