BANGOR (AP) – A third 911 emergency phone system malfunction has left public safety officials, technicians and FairPoint Communications frustrated and puzzled.

Because of failures in the system at the Penobscot Regional Communications Center in Bangor, emergency calls last weekend had to be routed through the Department of Public Safety in Orono.

Technicians were testing equipment at the Bangor center Tuesday and hoped to have the system back on line later in the day, said Tracey Erickson, a center supervisor.

During the month beginning April 17, similar but unrelated problems surfaced in the 911 system at the Cumberland County Regional Dispatch Center in Windham. Calls were shifted to the Maine State Police communications center in Gray.

The dispatch center in Gray suffered an unexpected shutdown in late May, a problem that was diagnosed as a software configuration issue.

Most systems in the state run on different technology and have not been affected, but it’s feared that the recurring problems are weakening faith in a lifeline that Mainers rely on to link people in emergencies with the rescue workers they need.

“We’re assured the problems are limited to those (few) systems, and that the majority of those of us that have the other type of system don’t have to worry about it,” said Sonia Moeller, vice president of the Maine Emergency Dispatchers Association.

“However, these little things keep popping up. Yes, we are concerned.”

FairPoint Communications, which inherited the systems when it bought Verizon’s telephone network in northern New England in March, said Monday it was working to correct the problems at the Bangor center, which dispatches emergency calls for 88 public safety agencies.

“We’re doing the diagnostics and analysis again, trying to identify this problem,” said FairPoint spokesman Jeff Nevins. “It’s a priority for us. We’re doing everything we can to get the center back up and operating.”