Comcast wants your old cable box, demanding that you swap it out for a new one.

Initially, the pitch sounds appealing. Who doesn't want the added interactive features, deeper mix of cable and web channels, and voice control now available with the X1 platform and cable receivers? To get it, you're going to have to give up your old box — losing your stash of championship game moments, comedy bits, favorite films, and never-to-be-rerun concert shows.

While satellite TV receiver/DVRs from Dish Network and DirecTV allow consumers to move or store shows on an external hard drive that can be plugged into a new receiver, that option isn't available with Comcast Xfinity or Verizon FiOS boxes.

According to a Comcast source, there's no way to transfer recordings directly from an old model to a new one. However, only about 5 percent of customers still have the outdated boxes.

There's no legal recourse for the loss of previous recordings. User agreements that are signed before activating gadgets hold that the maker or supplier can't be held liable for more than the cost of the hardware if or when the product fails to perform.

So which set-top boxes are being targeted? The relatively older ones (see below). Comcast's regional senior vice president Jim Samaha recently sent out a letter to those customers affected.

Germantown resident Tom Di Nardo ignored the first few letters: "I'm always getting mail from Comcast." Then this past weekend, warning messages started showing up on his TV every 15 minutes declaring his service was about to be disrupted.

"Older boxes like yours can't keep up with new features and will lose HD channels. So we'd like to give you a new one."

This elimination of high-definition channels on older cable boxes is happening because Comcast has changed the way it sends signals.

Initially, several hundred channels were pumped simultaneously through cable lines to a set-top box, where customers tuned in to the ones they wanted. Now, with the X1 platform and a far more refined MPEG-4 digital compression scheme, only the channel you've selected is streamed to the cable box as a much smaller file.

That radical change frees up the bandwidth to carry extra HD and Ultra-HD channels and, more important, faster internet service that Comcast may have to rely on if the trend to streaming video suppliers, like Netflix, Hulu, Sling TV, and Amazon, continues. The new tech also offers far more recordable program storage, "in the cloud," that won't go away if you change boxes again.

East Mount Airy resident Elayne Bender is already mourning the loss of favorite episodes of The Sing-Off and "classic Saturday Night Live bits" that will vanish when she swaps out her current cable box.

Di Nardo, a longtime classical music critic and author, is bemoaning the 18 hours of the Metropolitan Opera's Ring Cycle — a $16 million homage to Wagner's masterwork — that he dutifully recorded on WHYY's Y2 arts channel in high definition.

So that all is not lost, he's now in the midst of copying those shows through a DVD recorder — a product that Toshiba, Panasonic, and Magnavox quit making a few years ago but can still be found in limited quantities online. "The transfer to video disc is time consuming — it has to be done in real time — and the picture quality is standard definition, not that good," Di Nardo said. "But it beats recording the operas with a digital camera or a smartphone held up in front of the TV screen."

Obsolete Comcast cable box models
DCH3416, DCT6200, DCH3200, DCT6412, DCT3416, DCT6416, DCT5100, DCH6200, DCT3412, and DCT6208. If an installer is dispatched to your residence, a $60 service fee will be charged. However, if you can do it yourself, you pay nothing and get a free return label for the old box.