Former satellite TV provider EchoStar Corp. on Sunday will demonstrate its first product for cable companies at the industry’s trade show: a unit that can tune in television and act as a cable modem.

The SlingModem, made by Sling Media Inc., which is owned by EchoStar, will combine modem functions with its popular Slingbox, which lets users watch broadcast, cable or satellite TV shows on any Internet-connected device such as laptops or cell phones, even when they’re away from home.

For instance, it lets someone who subscribes to cable catch an HBO special on his laptop while he’s on a business trip in Japan.

The unit, to be sold through cable companies, at least initially, was first announced in January at the Consumer Electronics Show in Las Vegas.