An overview of the ASUS Xonar D1 PCI audio card is shown in the image below. The PCB is a brownish black, with a variety of silver and gold features onboard. It comes assembled with a full height expansion bracket, and as we will see later it also comes with a low-profile expansion bracket.
In addition to the typical connections on the rear panel of the card, there are a variety of headers on the edge of the PCB to be used for internal connections. Right behind the expansion bracket is a 9-pin header to be used with a case's front panel audio connections, farther down the same edge is a 4-pin "AUX IN" header for optical drives and/or tuner cards, and finally there is a 3-pin SPDIF out header to pass audio to certain HDMI capable video cards. There is another header labeled "JP2" on the face of the card, but I could not determine what, if anything, it did.
The card's expansion bracket is unique since it is colored black, and does not include any color coding to help with connecting speakers. Many sound cards place a colored ring around the 3.5mm plugs to identify what speakers are to be connected, and the ASUS Xonar D2X included the extra nice touch of illuminating each plug with the appropriate color. Here you have to squint at faint etchings of text labels in the steel, and I found a flash light was necessary to identify each plug during installation.
Taking a look st the five plugs above, the one on the far left is the most interesting. It serves triple duty as the optical digital audio connection, the line-in connection, and the microphone-in connection. With a front panel audio connection on your case you may be able to use more than one of these features at a time, and the design is obviously to allow this card to remain a low profile. The other plugs on the back include (from left to right); front speakers, side speakers, center / subwoofer, and back speakers.
The accessories included with the ASUS Xonar D1 are on the light side, especially when compared to the Xonar D2X. As pictured in the image below, you get a quick start guide, a driver and utility CD, a low-profile expansion bracket, screws for mounting the bracket, and a 3.5mm to optical digital audio adapter. While the disk suggests that "utilities" are included, the review sample only included drivers and PDF manuals on the CD. The ASUS website indicates that you receive a copy of the RightMark Audio Analyzer, and the box says that a copy of the ASUS Personal Media Processor Lite is included, but I didn't find either.