Berks County's 911 system is now up and running.

For 90 minutes Thursday afternoon, technical difficulties prevented the county's 911 communication center in Bern Township from receiving 911 calls, officials said.

A piece of faulty equipment called the controller is what caused the 911 blackout, administrators said.

The equipment is maintained by Verizon, but at the time of the 911 outage, the Verizon workers qualified to work on the faulty 911 equipment were on other calls in Lehigh and Montgomery counties.

"It was 90 minutes of absolute frustration and anger almost," said Carl Geffken, the county's chief operating officer.

During the 911 blackout, 155 calls went unanswered, authorities indicated.

The most severe 911 call was a controlled fire in Perry Township.

"That's just horrible. I hope they fix it ASAP," said Liliana Salazar from Reading.

And that's exactly what officials said they will be working on with Verizon.

"And most importantly, why did it happen and how to prevent from ever happening again," said Geffken.

Officials said they are currently working on a mass notification system that will inform residents all over Berks County should the 911 system go down again.