This is a rack-mount device for the kind of installations hidden away in an equipment room, not the kind of thing you normally have under the TV. It has twice the recording capacity of the consumer HR20-700, with up to 100 hours of HD. That indicates it has a 500GB drive, as the HR20 has 250GB. Technobob has a high-res image of the flier which clearly shows the back of the unit. It has a modem jack, two Ethernet ports, an eSATA port, two coax inputs (both appear to be satellite), one USB port, one S-Video out, one set of component video out, two composite video out, two stereo audio out, one digtal coax audio out, one optical digital audio out, one RS-232C port, one HDMI port, and one DLI port.
DLI is something most people are probably unfamiliar with, it is Digital Light Interface. Think of it as HDMI over fiber optics instead of copper wire. It allows for much longer runs between the device (the HR21 in this case) and the display, receiver, etc. The signal is effectively the same as on HDMI, including HDCP content protection. But the ability to do long runs allows for a centralized installation to server remote displays. There is a switch on the back of the unit which appears to select HDMI *or* DLI as an output. From the front panel it appears the unit outputs 480i, 480p, 720p, or 1080p – no 1080i.
It appears that this unit does not support antenna input, like the consumer devices do, so there is no recording of local ATSC channels. This is satellite only. I wonder why it has two Ethernet ports. Considering the nature of Ethernet, it is unusual to need more than one port on a device like this. No pricing is available, it looks like it will be on display at the upcoming CEDIA Expo (at DirecTV Booth 592), and it is rumored to be available in November.