Stay tuned ...

On the Feb. 18 episode of ABC hit “Lost,” something confusing will happen, a character will do or say something sinister, and a captivating mystery will be revealed. Of course, anyone not prepared for the big digital television switchover on Feb. 17 will miss out.

Or will they?

This week, Congress will vote on delaying the analog TV shutdown by about four months to June 12.

The U.S. Senate has already voted for the extension, and President Barack Obama has promised to sign the bill if it is passed by the House this week, according to The Associated Press.

So what the heck is the big change? Who does it affect? And why is this all going on in the first place?

Who will be affected

Anyone who watches analog television pulled from an antenna. That means if you’ve already got a pay service (cable or satellite) or a digital TV, you’re good to go. Those with antennae on top of the roof or “rabbit ears” on your set, keep reading.

What is happening

All full-power television stations in the United States will stop broadcasting in analog and switch to digital broadcasting. According to Edie Herman, spokeswoman for the FCC, anyone who does not have a digital television, a subscription to a pay cable service or a converter box will not be able to view any channels.

“It’s really important that folks act quickly and act now,” Ms. Herman said.

Why the conversion Is taking place

“A really important benefit of the switch is that it frees up valuable broadcast spectrum for public safety communications,” said Ms. Herman.

She said that digital is considered a more efficient means of broadcasting than analog. Consumers will notice improved picture quality.

How to make sure you’re ready (three options)

1. Purchase a TV converter box.

A converter box can be plugged into an analog television. Used in conjunction with your antenna, the box will keep analog sets running after the switchover. Tom Tolar, general manager of WRCB-TV, said conversion boxes need to be set on the day of the switchover, otherwise they will continue to search for analog signals.

Coupons were formerly available to offset the cost of purchasing converter boxes. However, according to Web site dtv2009.com, “the television converter box coupon program has reached its funding ceiling.” Consumers may still fill out an application on the Web site to receive a spot on a waiting list.

2. Buy a digital television.

3. Subscribe to a cable, satellite or other pay service.

Laurie Shipley, manager of government affairs at Comcast, said monthly subscriptions have remained consistent.

In December and January, local stations ran tests to allow viewers to check if they needed to upgrade their televisions to prepare for the change. Mr. Tolar said WRCB received fewer than 50 calls.

“I think there is going to be some disruption,” he said.

Where to get a digital converter box

Check major retailers. We found the boxes at Best Buy in Hixson, Kmart in Fort Oglethorpe and Radio Shack in Red Bank, for example. Converter boxes also can be ordered from a number of online and telephone resources, which are listed at the DTV Web site (dtv2009.com).