Yesterday, ye olde American Telephone and Telegraph; Ma Bell, reported resolving an issue that left many AT&T customers unable to call their friends on rival networks. The problem wasn’t a complete AT&T network outage, but specifically affected switching services between AT&T and rival networks.

So, What Happened?

We don’t know, and AT&T isn’t exactly telling. Anecdotal reports state customers were able to connect to other AT&T users, and mobile Internet access was unaffected. However, AT&T customers couldn’t dial their friends and family on rival networks. Nor could customers dial and connect to AT&T customers. This caused a cascading effect in which some Verizon customers reported an outage when there wasn’t one, because they couldn’t connect to AT&T’s network.

AT&T didn’t report the number of customers unable to make calls (which seems like something the FCC should require). Online snoopers were able to shine some light on the issue, however.

Down Detector reported users were having problems making calls beginning at 1pm on Tuesday with the number receding by 6pm that evening. New York, Chicago, Philly, Dallas, Pittsburgh, and Indianapolis were the major cities impacted by downtime. theSync’s staff are heavily grandfathered AT&T users and didn’t report issues in Washington, DC.

911 service was largely unaffected except for minor 911 outages in Camden and Philadelphia.

The incident comes on the heels of major outages and issues with AT&T. A 12 hour outage impacted tens of thousands of customers including El Jefe. In March, AT&T was hacked and the hackers absconded with social security numbers in that heist.

As always, keep your credentials secure. And change your passwords regularly.

-MJ