Ellis County was one of several counties affected late Thursday’s initial 911 service disruption. Dallas County and Wilmer were also affected. Operations returned to normal after the nationwide outage that affected emergency-calling services around the country. Several North Texas municipalities reported 911 service disruptions starting late Thursday, with service briefly restored early Friday morning before going down once again. The outage is the system’s second in four months after 26 years without incident, following a glitch in September spreading across 13 North Texas counties. Cause of the initial outage related to a national Century-Link rolling outage is unclear, ending before 6 a.m. Friday, according to the North Texas emergency district. According to its website, the district serves about 1.9 million people in 13 counties.