The phrase "dial system" refers to a method or mechanism that uses a circular device with numbered markings to make selections or adjustments. It involves turning or rotating the dial to choose a specific option or setting. Full definition
There were also two dial systems on the back of the case, each with a pin that followed its own spiral groove, like the needle on a record player. (smithsonianmag.com)
The custom dial system is pretty awesome, too. (geekwrapped.com)
The new navigation system also featured voice dial systems and the ability to enter destinations by voice address while driving. (en.wikipedia.org)