 In the 1960s and 1970s, such exhibits usually included videophones.While such technology has actually existed since the 1960s and has been developed and improved since, many new mobile phones can now make video calls and use of a home web camera on an instant messaging client and sending of pictures via cell-phone cameras has become prevalent.Other common features of "home of the future" exhibits include centralized and automated control of all appliances, and the use of voice commands to operate devices.