Since Internet service started arriving in households in the mid-1990s, the companies and engineers behind its proliferation have been driving to the same technical end: putting optical fiber, with its sky's-the-limit data capacity, in homes instead of copper wire and coaxial cable.

This week, Comcast, the leading provider of Internet service in the Twin Cities, quietly began offering to run fiber to homes for the first time in the metro area.

With a fiber line, customers will be able to access Comcast's newest, fastest Internet service for homes. Called Gigabit Pro, data flies in both directions at 2 gigabits per second. That's 2,000 megabits per second, or about 80 times the 25-megabits per-second download speed that's now typical for Twin Cities households.

But the service is likely to attract relatively few early takers. It's available to a sizable portion of the metro area but not everywhere: about 400,000 of the region's 1.2 million households can get it. It will be priced at $299.95 per month on top of an existing Comcast cable TV or phone package and require an installation fee that will vary based on engineering factors. Comcast executives said they don't plan to advertise the service.

"This is designed for the most advanced digital homes of the future," says Jeff Freyer, Comcast's regional vice president in the Twin Cities.

Even so, the development is a milestone in the evolution of the region's communications infrastructure. Telephone and cable TV companies in the 1990s began adding fiber at the center of the Twin Cities networking web. But the outer strands, the wires that went to homes, remained low-capacity copper wires or slightly higher-capacity coaxial, chiefly for cable TV.

The telecom and cable TV firms then strung fiber to businesses, government agencies and education institutions with big data needs and the means to pay for upgraded lines. New firms emerged that also laid fiber lines, competition that spurred telephone and cable TV providers to push the technical limits of copper and coax into handling faster data speeds. But because fiber conveys data in the form of light, its capacity is perceived to be limitless. While engineers have pushed the boundaries of copper and coax, the bandwidth, or capacity for data, in fiber is far greater.

"In the end, fiber will always be the preferred medium because of its capacity," said Michael Howard, analyst at IHS Infonetics in Campbell, Calif. "They are continuing to expand the capacity on fiber way beyond anything they can do on copper or coax or mobile."

Locally, Comcast is competing chiefly with CenturyLink, which has announced plans to offer 1-gigabit service in an unspecified portion of the metro area, and US Internet, which buried optical fiber in much of south Minneapolis and for the past year has offered 10-gigabit-per-second fiber-to-the-home service in that portion of the city for $399 a month. It also currently offers 1-gigabit service, and plans to roll out 2.5-gigabit and 5-gigabit services in 2016.

Even as the Twin Cities became Comcast's latest market to offer fiber-to-the-home, the Philadelphia-based cable and Internet giant gained national headlines this week for rolling out a new modem that makes it possible to for the firm to deliver 1-gigabit-per-second speed over coax. That means Comcast will soon be able to offer home customers a sizable jump in data speed without putting in fiber.

"Offering multigigabit speeds is the way of the future," Freyer said. "We're going to push the line and make sure we're the fastest out there."

For now, Comcast added a 250-megabits-per-second service to all Twin Cities customers, priced at $149.95 a month, to its existing offerings of 25, 75 and 150 megabits. All are download speeds; upload speeds are slower.

Customers who want Comcast's Gigabit Pro will need to have their home and property inspected by a Comcast technician, who will confirm whether fiber can be installed, determine how to do it and what it might cost. Installation would be simple and relatively inexpensive, for instance, for a home near an access point from which fiber is strung along utility poles to it. The job would be more complex and costly for a home with fiber run underground.

The gigabit speeds that are available with fiber connections are most noticeable in the transfer of video and other data-intensive information. Comcast says a typical HD movie will take 20 seconds to download on its fiber-driven Gigabit Pro service, compared to 27 minutes on the 25 megabit service that most Twin Cities households now have.

Such a difference will be more impactful in future years as higher-resolution UHD and 4K TVs become more common and the data increases to deliver their ultra-clear pictures.

Evan Ramstad • 612-673-4241