In less than a year, South Dakota residents will be required to dial "605" before calling every number in the state. But the state is encouraging residents to start getting into the habit now. The change is a result of a nationwide campaign to turn the number "988" into a suicide prevention line. Here's what you need to know: What will be the new dialing procedure? Beginning on April 24, South Dakotans are encouraged to start using 10-digit dialing to make all local phone calls, the South Dakota Public Utilities Commission said. Currently, the "605" area code is not required when making a call in-state on a cell phone or to local numbers on a landline phone, but that will change next year, so the PUC wants to change people's habits now.