I just checked online and the HD-A2 does not have a coax output. Here is an exerpt from a CNET review...
"What's missing? Well, if you step up to the HD-XA2, you get everything on the HD-A2 plus multichannel analog outputs, a coaxial digital audio output, and an RS-232 port. Those connections can certainly be useful, but they're not huge omissions if you have an HDMI-capable receiver and don't need the RS-232 functionality. The step-up HD-A20 and HD-XA2 also offer 1080p output over the HDMI output--instead of the HD-A2's 1080i output. We'll discuss the difference in the performance section.
Savvy home-theater enthusiasts will also notice that the HD-A2 lacks the ability to output in 24 frames, which some claim can reduce judder. The ability to output in 24 frames per second is marketed as a cutting-edge feature, but so far in our tests we have not been able to see any benefit from using this feature. We will continue testing the benefits of 24-frames-per-second output, but as of now we don't consider it a significant omission."
