Comcast is expected to flip a switch Tuesday in Houston that will turn 50,000 of its customers' home Wi-Fi routers into a massive network of public Wi-Fi hotspots.

Comcast residential Internet subscribers with one of the newer cable modem/wireless router combos will show a public network called "xfinitywifi." Other Comcast customers will be able to connect to it free.

By the end of June, there will be 150,000 such hotspots in the greater Houston area. It's part of an initiative that will see 8 million Wi-Fi hotspots accessible to Comcast customers around the country by the end of the year.

The move could also lay the foundation for Comcast to get into the wireless phone business with a network that blends Wi-Fi and traditional cellular service.

Amalia O'Sullivan, Comcast's vice president of Xfinity Internet Product, told the Houston Chronicle that the goal is to make it easier for "friends and family" to use each other's Comcast home Wi-Fi networks.

"Instead of coming over to your house and saying, 'Hey, what's your Wi-Fi password?' your friends can just connect to the Xfinity Wi-Fi hotspot," O'Sullivan said.

The free network will be on by default for customers who have an Arris Touchstone Telephony Wireless Gateway Modem, which Comcast has been distributing for about two years in Houston. The black plastic device is tall, narrow and has the word Xfinity on the front. It costs $8 a month to rent, and is the standard equipment being issued to Comcast customers who don't buy their own modems or routers.

Comcast spokesman Michael Bybee said the Xfiniti Wi-Fi hotspot will broadcast only in those cases where customers are using the Wi-Fi feature of the Arris device. Customers who have their own Wi-Fi routers won't be broadcasting the hotspot.

Bybee said the network will be activated in "waves," with the first 50,000 switched on Tuesday afternoon. The remaining 100,000 will be phased in through the month.

Customers were notified of the plan in a letter last month, Bybee said. An email notification will be sent after the service begins.

Less than 1 percent opted out

For those who may be unnerved that their private home routers suddenly are offering public access to their Internet connections, the hotspot can be disabled. Customers can either call Comcast customer service and ask that it be turned off, or go to the account page on Comcast's website and disable it themselves. (Log in at customer.comcast.com, go to My Account and then Users & Preferences. Look for the "Manage Xfinity Wi-Fi" link.)

In other areas where the Xfinity Wi-Fi network has gone live, less than 1 percent of customers have opted to turn it off, Bybee said.

O'Sullivan said the Wi-Fi network is separate from private home networks and doesn't give those who connect access to residential customers' devices. Up to five people can connect to the hotspots at a time, and O'Sullivan said the network is designed so guests who connect won't slow down the residential customer's connection.

Comcast customers can find business hotspot locations on the Web at wifi.comcast.com, or by downloading the Xfinity WiFi app for iOS and Android devices to a smartphone or tablet. Bybee said the residential hotspots won't show up on the map or apps. Those who want to connect to a residential hotspot will need to use the Wi-Fi-connection feature on their computers or mobile devices.

Because of the limited range of home Wi-Fi routers, don't expect to be able to drive down the street and hop from one residential hotspot to another, O'Sullivan said. While connections will be available outside some homes, the signal quality drops off quickly the further a user gets from the router.

"It's really for when you need a connection in the places that matter the most, and hopefully the places where you dwell the most," she said.

Comcast customers will have to sign in to any Xfinity Wi-Fi hotspot only once. After that, they will automatically be connected when one is available.

Non-customers will be able to use the hotspots as well, getting a very limited amount of free time, O'Sullivan said. If they need more time, they'll pay a fee.

The initiative is an attempt by Comcast to compete with wireless carriers such as AT&T, which has a large network of Wi-Fi hotspots via businesses, including in major chains such as Starbucks and McDonald's. Comcast also has a network of business customers that provide hotspots, and it has established Wi-Fi beachheads in public places such as stadiums and parks. For example, Comcast offers Wi-Fi service for its customers at Minute Maid Park.

Wireless phone network?

Spencer Kurn, a partner with New Street Research in New York, said Comcast is laying the foundation for a possible wireless phone network that would switch seamlessly between Wi-Fi and traditional cellular connections.

"We think it's not a matter of if, but when," Kurn said.

Indeed, in a document filed with federal regulators as part of its $32 billion plan to buy Time Warner Cable, Comcast said a network such as the one enabled by its residential hotspots "could make a 'Wi-Fi-first' service, which combines commercial mobile radio service with Wi-Fi …"

Kurn said Comcast last year sold wireless spectrum to Verizon, and part of that deal gave Comcast access to Verizon's wireless network. Thus, a Comcast-owned wireless phone service could hand off callers between its Wi-Fi networks and Verizon's cellular one.

O'Sullivan said there currently are no plans to enter the wireless phone arena, but that it is conceivable in "the longer term."

Comcast is turning on the residential Wi-Fi hotspots in multiple cities this month. The network is already up and running in many cities where Comcast provides service, including Philadelphia and Indianapolis. By Wednesday, Bybee said, there will be 3 million of the hotspots nationwide.