How SPOT Works
SPOT uses FM broadcasting, like the kind picked up by a radio, to deliver Web-based data to Smart objects. Smart Watches receive more than 200 channels of information that are broadcast on a radio spectrum leased by Microsoft.Microsoft created the Microsoft DirectBand Network to send data to Smart Watches and other SPOT objects. DirectBand consists of two components: a special chipset in the watch that houses the radio receiver and a nationwide, wide-area network (WAN). The WAN is built on FM-subcarrier technology.
Subcarrier frequencies are usually above the normal frequency range used for audio and are modulated to carry data. For instance, in analog TV transmissions, a subcarrier frequency is used to carry information about color and other broadcast information. DirectBand transmits Web-based data on subcarrier frequencies using radio protocols designed specially for Smart Watches.
The DirectBand broadcast range covers 100 metropolitan areas in the United States and five major cities in Canada. In order to get this wide coverage, Microsoft partnered with ClearChannel and Infinity Broadcasting. This partnership allows DirectBand to broadcast data over a large, existing FM radio infrastructure rather than having to create its own.
 Photo courtesy The SPOT Group The SPOT Coverage area extends to 100 metro areas around the United States and five major cities in Canada. |
To add DirectBand to an existing station, technicians install a piece of hardware called a broadcast generator. The broadcast generator injects the data stream directly into the FM broadcast that is transmitted to Smart Watches. The data originates from the DirectBand Data Center in Tukwila, WA. The streams are encrypted and transmitted from MSN through private frame relays, satellites and WAN networks.
MSN Direct is the Web-based component of the Smart Watch system that acts as a user interface for subscribers. The Web site can be used to purchase, activate and administer Smart Watches.
 Photo courtesy MSN Direct The MSN Direct Web site acts as a user interface for the Smart Watch. |
To start a Smart Watch, a user must create a profile using a free .NET account. The activation process and setup includes entering billing information, location and the particular type of Smart Watch the user owns. Once the account is set up, the user can add, delete and modify the channels that are sent to the Smart Watch.
 Photo courtesy MSN Direct A user can add and delete channels on this page. |
The channel system is based on "blocks." For instance, the test watch we used for this article had 1,000 blocks available on it. We chose from a list of channels, each of which had a block value ranging anywhere from 20 to 480 blocks. We were able to add channels up to our allotted 1,000 blocks. When we deleted a channel, its corresponding number of blocks became available.
In the next section, we'll see what's inside a Smart Watch.
