The South Dakota Public Utilities Commission has to decide if phone books are going the way of the hand-written letter. Phone book publisher Dex is transitioning from paper directories to online listings in a number of states. Two weeks ago the state PUC heard from representatives of Dex, Qwest, and CenturyLink, who want to transition away from printing phone books in South Dakota and publish directories online. The commission delayed making a decision until its hearing on Jan. 19.