The Kindle DX includes an area on its main printed circuit board (PCB) that almost certainly implements electrical connections for a Wi-Fi radio. The area includes sites for an integrated circuit package or radio module, various discrete components, and a ceramic antenna. These PCB features are exposed in a photo from a recent tear down of the Kindle DX at the Rapid Repair website.
None of these Wi-Fi related PCB positions are populated with components in the currently shipping Kindle DX, but if they were populated, the Wi-Fi antenna would reside near the upper left-hand corner of a front-facing Kindle DX.
The PCB features suggest that Amazon is in a technical and manufacturing position to introduce a Wi-Fi radio into its Kindle line of e-readers at any time. A decision to introduce a Kindle with Wi-Fi may depend on the results of Amazon’s negotiations with wireless carriers around the world. Wi-Fi would be a reasonable option for wireless connectivity in any locale where cellular service is unavailable or too expensive. Given the intense global competitive environment in e-readers and e-publishing, and the rapid pace that Amazon has been keeping in Kindle developments, announcements relating to international availability for Kindle products should be expected soon.
For more discussion about the potential for use of Wi-Fi radios in future Kindle products, see this previous post at Kindle Zen. For photos from the surgery on a Kindle DX, see this web page at Rapid Repair.
Update 10 July 2009: We have tentatively identified the RF module that mates to these unpopulated PCB features in the Kindle DX. It is the Murata SyChip model LBWA18HEPZ and it implements a complete IEEE 802.11b/g Wi-Fi radio in a tightly integrated package. This power efficient Wi-Fi module incorporates the well regarded Marvell 88w8686 Wi-Fi chip and the module is manufactured by Murata in large volumes. The Marvell chip also appears in the Wi-Fi radio for the Palm Pre and the chip is supported by Linux device drivers.
This Murata module seems to be quite an appropriate choice for a Kindle Wi-Fi radio. The module is mature, cost-effective, and appropriately low power. This choice can be viewed as another in a series of astute, conservative design decisions by the Kindle DX hardware team. To see the PCB implementation of a Wi-Fi radio using this Murata module in a different application, check out the DevKit270 from Embest.
Of course, these PCB features in Kindle DX do not necessarily portend a business decision by Amazon to bring Wi-Fi to Kindle. The PCB features could just be a left-over from Wi-Fi prototyping or included simply for use as a lever in negotiations with wireless carriers. It would not be entirely surprising if a different motherboard and different radio solutions appear in future DX-style Kindles for international markets.