Technology is always progressing . Today , many modern devices can be controlled by touch or voice . This has led to some traditional electronic controls – such as dials and switches – being replaced with new technologies . Digital displays have also become increasingly common . For example , digital number readouts have long replaced the hands on many clocks . Many other devices also now operate purely with digital tools instead of mechanical systems . But some expressions and idioms used by English speakers still describe older technologies . First , let's talk about dials . These controls are used for changing settings on a piece of equipment , like a radio or old television . We use the dial to tune in to a specific channel . That's where the expressions dialed in and tuned in come from . If we are dialed in or tuned in to a radio or television program , we can hear it clearly . There is no noise or static . The same can be said when using these terms in personal conversations . For example , if you are dialed in to a project or problem , you know exactly what needs to be done . You are thinking clearly about it and remain very focused . And when you are tuned in , you understand clearly what is going on around you . “Don't touch that dial ” and “stay tuned ” are two ways to tell someone to keep watching or listening to a program . Now , let's talk about switches . These are built to either be off or on . There are no in-between settings like with a dial . So , when we flip the switch , we make something happen quickly and easily . It can also mean that we suddenly change something . Let's listen to an example . The restaurant's change to all organic food happened slowly over time . It wasn't a matter of flipping a switch . Now , for our last expression -- to move the needle . Needles on measuring devices like a scale move to show a desired level has been reached . So , when something moves the needle , it causes a noticeable change in something , usually for the good . Don't forget to tune in again for another story about American English expressions .