Originally, electronic devices such as radio transmitters, wireless communications systems, and the like, were base stations, operated at fixed locations, typically with large antenna towers. Widespread use of automobiles gave rise to smaller devices operating at 6 volts. In the 1950s, the transition to 12 volt automotive electrical systems gave rise to a large number of 12 volt devices, such as two-way radios, referred to as mobile rigs. A large industry, with companies such as Motorola (Motor-ola) sprung up to support the growing need for mobile devices, such as taxicab radios, police radios, and other 12 volt underdash equipment, as well as trunk mount systems. Today there are a wide variety of mobile computing platforms, including dash-mount VGA displays, and computers that can provide GPS and other navigation functions for automobile users.