The Linksys Media Center Extender DMA2100 is the little brother of the Linksys Media Center Extender DMA2200. When we say "little brother", we're not just talking in a features sense; at 170x113x188mm, the DMA2100 is about a third the size of the chunky 2200. This does make it more suitable for a lot of home installations, simply because it's both more subtle, and with its smaller size, it will more easily fit into the DVD-style spaces that many entertainment units come with for switching boxes, DVD storage and the like. Linksys must be doing something interesting with either airflow, circuit boards or both, as the size difference between the is far more than just a DVD player would suggest.
Like the DMA2200, the DMA2100 ships with 802.11n wireless capability, although it drops the number of installed external antennae from three to two. It ships with the same black Windows Media remote that the 2200 uses, which can make for interesting powering/command conflicts if you've got both installed. The same remote can also run an Xbox 360, which is a more likely combination in both homes, but also carries the same potential mix up woes.
In a features sense, the DMA2100 is the DMA2200, but with the upscaling DVD player ripped out of the middle. To borrow from our review of the 2200, then:
"The 2100 supports a variety of formats including MPEG-1, MPEG-2, WMV9, XviD and H.264 video codecs. It has audio support for PCM, MP3, Dolby Digital, WMA and WMA Pro. Picture support includes JPEG, PNG, BMP and GIF. This lot should make most people happy, but there will certainly be one or two of you annoyed with the exclusion of certain formats.