PORTLAND – FairPoint Communications is considering upgrading some cables after another 911 glitch that rendered the Cumberland County emergency dispatch center’s system inoperable. Unlike past glitches, no emergency calls went unanswered.

A switching station in Windham failed when its batteries died during power outages caused by a gas leak and a thunderstorm on July 18. The Cumberland County emergency dispatch center’s system failed eight hours later.

Public safety officials said new backup systems put in place after 911 system failures last spring worked as planned, and all emergency calls were answered.

During the switching station failure, county dispatchers transferred 911 calls to the backup center, and Gray dispatchers then relayed the information to county dispatchers, who were using cell phones. Dispatchers continued to use radios to direct emergency vehicles.

William Holmes, director of the Cumberland County Regional Communications Center, said he’s concerned about the latest glitch but he’s happy with the response from FairPoint.

“I am very confident that FairPoint has put safeguards into place that if a caller dials 911, those calls will get answered and the person will get a dispatcher response,” he said.

Between April and June, emergency communications systems at the Cumberland County center, the state dispatch center in Gray and the Penobscot County regional center all experienced problems receiving 911 calls. The most severe problems were in Cumberland County’s system in Windham, where seven system shutdowns in April and May left callers getting no answer, in one case for as long as an hour.

The latest problems again affected Cumberland County’s system in Windham on July 18 after a gas leak that shut down the power grid in Gorham and then after severe storms that tore through neighboring Windham, causing additional power outages.

An alarm on the Windham station failed to alert FairPoint that it had no power, and the station failed when the batteries were drained.

The dispatch center itself was unaffected because it has two backup generators, but it couldn’t receive calls routed through the Windham center. FairPoint service was restored thanks to a generator that was brought to the Windham switching center.

FairPoint is studying the feasibility of running about 11/2 miles of fiber-optic cable between the switching station and the dispatch center. The fiber-optic cable would allow the system to continue to operate even if it lost power.

The upgrade would be costly and could take six months, officials said. In the interim, the company might install additional batteries and a backup generator in Windham.