The HR21 is DirecTV's primary HD DVR. It features a 320GB hard drive and dual DirecTV tuners, which allows you to record two shows simultaneously or watch one show while you record another. The box supports MPEG-2 and higher-quality MPEG-4 signals. It does not contain internal ATSC tuners to pull in over-the-air HD content; if you live in area where DirecTV does not yet offer local channels in high-def, you should request the HR20 instead, as it does offer the internal ATSC tuners.

Additional Resources
• Read more satellite receiver and HD DVR reviews from HomeTheaterREview.com's staff.
• Find a plasma HDTV to get the most out of the HR21.

The back panel contains one HDMI, one component video, and one S-video output, plus dual composite video outputs - which allows you to send an SD signal to a second room (you can only watch the same content being displayed in the main room). On the audio side, you can output PCM or Dolby Digital 5.1 signals via the HDMI, optical digital, or coaxial digital audio outputs; two stereo analog audio outputs are also included. The box sports two Ethernet ports: One port allows you to add the box to your home network to order video-on-demand titles and utilize limited media-streaming functions (if you have an Intel Viiv PC); the other port serves as a pass-through to add attach other networkable devices. The HR21 also has two USB ports that are currently inactive, as well as a phone jack for pay-per-view and Caller ID display and an eSATA drive to add a larger external hard drive.

The HR21 supports 480i, 480p, 720p, 1080i, and 1080p resolutions; DirecTV recently announced plans to offer some video-on-demand content at a 1080p resolution and has upgraded the HR21's firmware to support 1080p output. The setup menu also includes a native option to output every channel at its native resolution, which allows you to bypass the box's internal (and mediocre) scaler. The setup menu includes some other nice features, such as the ability to designate a color for 4:3 sidebars (dark gray, black, or gray), which is especially beneficial for plasma owners who are concerned about image retention. You can also designate an aspect ratio for 4:3 content (original format, stretch, crop, or pillar box); the remote's format button allows you to scroll easily through the choices.

As for its DVR functionality, DirecTV's interface is solid and generally easy to navigate. Most of the desired recording options are here, such as the ability to set first-run-only recordings and the option to start recordings early or add time at the end. The recordings list provides an indicator that shows you how much hard-drive space is remaining, and the HR21 has a nice, long 90-minute buffer, plus a 14-day program guide. You can schedule programs remotely via the DirecTV website, and the box does not have to be connected to your network to do so. The number of HD movies offered via DirecTV's video-on-demand service is solid and growing daily.

The supplied remote control lacks backlighting, but the buttons are arranged in an intuitive manner. It can control the HR21 via either IR or RF, and you can program the remote to control your TV and two additional components. The box itself has a nice step-up look, with a gloss-black finish and a clean button layout. The front panel features a navigation wheel with a glowing blue ring, plus buttons for power, guide, menu, record, info, active, and resolution. Four LEDs indicate the resolution of the current channel. The Active button launches DirecTV Active, which provides access to local weather, lottery, horoscope, and customer service information.