Now that analog TVs are no longer being manufactured and nearly every TV is capable of displaying high-definition (HD) programming, the popularity of HD cable is soaring. However, many cable subscribers are not getting the full experience of this service because they have yet to upgrade their HD cable boxes. It is widely believed that everything required to view HD programs is already included with the TV, but this is only true for channels broadcast through the air. Viewing HD cable programs requires either a Cablecard or an HD cable box.
What is HDTV?
HDTV was introduced in 1998, but programming choices were nearly nonexistent at that time. Today, almost every cable network offers programs in HD, but many cable subscribers are still viewing their favorite shows in standard definition (SD) because they are confused by the technology and all the new terms referencing digital television (DTV) and HDTV.
The primary difference between SDTV and HDTV is resolution, which defines how crisp and detailed images are when displayed on TVs. Television images are made up of thousands or millions of small, colored dots known as pixels. Older televisions using cathode ray tubes (CRTs) display a maximum of 525 rows of pixels, and SD programs only use 360 to 480 of those rows. New, flat-screen TVs are capable of displaying either 720 rows of pixels or 1,080 rows. HDTVs that can display a maximum of 720 rows have resolutions of 720p while those capable of displaying 1,080 rows have resolutions of 1080i or 1080p.
Many people confuse DTV with HDTV, but these two terms are not interchangeable. Today, all television programs are digitally broadcast, and all HD programs require DTV. However, not all digital programs are HD. The term digital simply refers to the fact that images and sounds are converted into binary code before being transmitted, and DTV still allows for programs to be displayed at the SD resolution of 480p.
Another difference between SDTV and HDTV is the aspect ratio. Although digital SD and HD both use the widescreen aspect ratio of 16:9, programs produced before DTV became mandatory often use the older, nearly square, aspect ratio of 4:3. When widescreen video is displayed on old TVs with the 4:3 aspect ratio, rows of black pixels are displayed above and beneath the video image, creating a format known as letterbox. When a program with a 4:3 aspect ratio is viewed on a widescreen TV, it is shown with black columns on either side, which has come to be referred to as pillar-box format.
The Importance of an HD Cable Box
As previously stated, it is not enough to simply purchase a new TV to display HD programming. Three other elements are required before an HDTV can be used to its maximum potential in conjunction with cable TV: HD service, an HD cable box and an HD cable. Because of the additional costs associated with the development and airing of HD programs, most cable companies charge a premium for HD service. Cable companies control access to HD programs by putting HD versions of each network on separate channels, and customers who do not pay the fee cannot access these HD channels.
Even if a cable subscriber has an HDTV and pays the HD fee, the channels will not display without an HD set-top box (STB). Cable customers who have recently upgraded to an HDTV and HD cable service must exchange their old STBs for Cablecards or STBs that are capable of decoding HD signals. Cablecards are a relatively new technology that gives viewers with digital-ready TVs the ability to view HD cable channels without using separate converter boxes. However, not all TVs have the necessary slots for the cards, and the cards have limited features.
The final element required for viewing HD programs is an HD cable. The standard coaxial cable used by cable companies does not efficiently carry HD signals from a cable box to a TV. This means that even if a cable subscriber has an HDTV, pays for HD service and upgrades to an HD cable box, he or she will still not be able to view HD programs without the proper cable. The best cable for connecting an HD box to an HDTV is an HDMI cable.
Choosing an HD Cable Box
Most customers receive HD boxes by leasing them from their cable companies, and those who choose this popular option have no say in what type of STBs are available to lease. Cable companies usually have only two or three models in service, and customers are given whichever model is on-hand at the time. However, cable companies are bound by law to allow customers to purchase and use third-party cable boxes. Most of these retail STBs still require Cablecards, so unless a particular model has unique features or capabilities, such as a digital video recorder (DVR), it is not worth the hassle to buy one of these boxes.