Thousands of riders rely on “NextMuni” stop predictions throughout San Francisco to tell when the next bus is on its way, but some of those LED readouts are malfunctioning in bus stops across The City.

Digital displays at dozens of bus stops, which, for instance, would show “10 minutes” for the next bus, began reading “Registering…” as early as last week.

The culprit is a systems migration for AT&T’s wireless networks, according to the San Francisco Municipal Transportation Agency, which runs Muni. AT&T is moving away from its 2G networks and toward 3G, which has impacted some signs, according to SFMTA spokesperson Paul Rose.

The system upgrade caused 67 of The City’s 867 signs to display “Registering…” during peak hours. In addition to those signs, others are also undergoing maintenance or repairs due to hardware issues, Rose said.

“We get a report everyday of what the status is and what is being worked on,” he said, and those issues “are being addressed.”

AT&T’s 2G network formed the backbone of wireless communication in the early mobile phone-era of the 1990s. Those who played the game “Snake” on their Nokia phones are an example of users of that “2G” network — short for second generation.

The NextBus prediction system, which is used by transit agencies nationally, also depends on this 2G network for GPS trackers aboard buses to coordinate with stops to display arrival predictions.

Many telecom companies are turning off their old 2G networks as the mobile phone-era looks to 3G and 4G as standards. In a statement on AT&T’s website, the telecom said it hopes to turn off its 2G network by the end of 2016.

Rose said the SFMTA is “working closely” with AT&T to understand their schedule to roll back the 2G network.

Future NextMuni outages may occur as AT&T continues to close the 2G network. Rose said the SFMTA is exploring whether it can delay some of that rollback to lessen the impact on NextMuni.MuniNextBusNextMuniSFMTATransit