After much watching of the internet auction site, I was finally able to procure two of these devices:
What is this thing???
It's a 455kHz to 12kHz IF converter that fits in an empty filter slot on your Yaesu FT-817, 857, 897. Why? Well, it gives you a 12kHz audio output that can feed your PC soundcard input, and allows you to use DRM decoding software like DReaM and Sodira, and also allows you to leverage software like SDRadio and others which essentially give you SDR demod and filter capability with your FT-8xxx series.
This is different from the RTL dongle approach, and you trade off a wider bandwidth for better sampling rate.
Works great. DRM decoding is on par with my Flex radio, and being able to use the brickwall filters and noise reduction of HDSDR and SDRadio is a nice addition to the radio.
I'm presently using one on my FT-857D and will be installing the other on my FT-817ND. http://subdimensions.com/2012/12/28/filtro-drm-e-sdr-if-per-yaesu-ft-897-ft-857-e-ft-817/