A federal judge is set to decide whether Chicago police officers should have received overtime pay for answering work-related calls and emails after hours, a case that could help clarify what it means for an employee to be off the clock in the age of smartphones, reports the Associated Press .

At the end of a bench trial, U.S. Magistrate Judge Sidney Schenkier heard closing arguments Monday in a class-action lawsuit brought by Chicago Police Sgt. Jeffrey Allen and 50 other members of an organized crime unit. They claimed the city owes them millions of dollars in back pay for work they performed on department-requisitioned BlackBerry phones.

A central question in Chicago is whether there was an unwritten rule requiring that officers stay engaged on their phones and responded to inquiries from superiors 24 hours a day.

Schenkier is expected to rule within several weeks on the Chicago case, which is one of several nationwide that could help draw a clearer line on whether employees must be compensated for answering calls or responding to emails after hours.