Failure of a key piece of Comcast equipment in Burlington knocked out cable and cellular service to customers across Whidbey Island and in Skagit County for about one and half hours on Wednesday evening.

A company official confirmed that the problem began shortly before 10 p.m. A device in a power relay system at a signal distribution center broke, and it wasn’t fixed until about 11:30 p.m.

Service was restored immediately for most customers, but an unknown number of customer modems failed to return to service and required visits by technicians the following day.

Comcast records outages by the number of devices, not postal addresses, and estimates are as many as 13,000 devices on Whidbey were affected, according to Walter Neary, a company spokesman.

“Every time something like this happens, we look at how we can do things differently to further improve reliability,” wrote Neary in an email. “We know Xfinity products and services are essential in people’s lives; we regret the inconvenience and are grateful for our customers’ patience.”

The equipment failure was in a facility called a “head end,” a hub where video and Internet signals are assembled, monitored, and sent to and from customers.

They’re recognizable by their large dishes, Neary said.

Though the failure was with Comcast, the interruption was broader. Residents from Clinton to Oak Harbor, and some as far away as Anacortes, reported losing cellular service with phone carriers such as Verizon and AT&T.

Many networks are interconnected, and it’s possible that, when Comcast’s equipment lost power some customers with those carriers lost cell service as well, Neary explained.

The outage also affected I-COM, Island County’s 911 dispatch service. The ability to receive and relay 911 calls was not affected, but certain electronic devices were offline.

According to Systems Administrator John Diamond, I-COM has a fiber network or Ethernet private line with Comcast that utilizes two pathways. The dual lines offer a redundancy or safety net for I-COM. When the provider lost its connection at the Burlington facility, both pathways went dark.

“There was about a one-hour down time where we could only wait for them to get it fixed,” Diamond said.

Comcast technicians jumped on the problem right away and were very “efficient,” said Diamond. The service interruption for I-COM was from 9:41 p.m. to 10:39 p.m., he said.

Emergency response agencies were all affected but in different ways. Police, fire department and hospital ambulance units all lost connection to vehicle computers, which provide information about calls such addresses. IP-based radios were also impacted, but only for South Whidbey Fire/EMS.

North end fire agencies and police have redundant systems that shielded them from any radio blackout.

South Whidbey has some as well, but still wide areas received poor reception, said Jon Beck, deputy chief for South Whidbey Fire/EMS. It has to do with the location of redundant transmitters operated by Whidbey Telecom, he said. They weren’t affected but aren’t as numerous, so signals had trouble reaching fire officials in certain areas.

“I live far south on the island, and I really couldn’t hear anything because it was so far away from those transmitters,” Beck said.

The outage was disruptive, but the district was still able to receive 911 calls, he said.

No calls were missed.