Conformity Magazine - September 2007 - (Page 34)

device has difficulty demonstrating compliance with the DFS requirements, this process can take much longer. Furthermore, since the majority of the products currently affected by the DFS standards are 802.11a products (access points, routers, PCMCIA cards, etc), the testing requirements assume that the device will be compatible with the Microsoft Windows operating system, and be able to stream an approved MPEG file during the testing process. While many products affected by the DFS requirements can meet these criteria, there are others which cannot. If a product manufacturer is unable to meet these requirements, they must seek approval from the FCC for the use of an alternate test method. While the alternate test method will likely employ a simple alternative process designed to create at least 40% traffic on the access point that is part of the DFS test set-up, it may take the FCC several weeks to several months in order to provide a definitive response to the manufacturer on this issue. Naturally, the testing and certification process is essentially at a standstill during this time. For these reasons and others, our next piece of advice is don’t underestimate the FCC turn-around time for DFS grant approvals. Stay Informed and Be Ready for Additional Changes to DFS Testing Requirements In July 2006, the FCC’s DFS requirements went into effect for all new products operating in the affected frequency bands. On July 1, 2007 the second deadline will go into effect, which will require that all products (even those that were on the market prior to June 2006) meet the DFS requirements. It appears that most manufacturers have been preparing for this deadline, as a flurry of Class 2 permissive changes have already been filed in the first half of 2007. Once July 1, 2007 passes, there will no longer be exemptions for any devices that operate in the frequencies affected by the DFS standards. Manufacturers whose products were approved to use the 5250-5250 band prior to July 2006 but which have not applied Pulse Width (μs) Bin 1 Bin 2 Bin 3 Bin 4 Bin 5 Frequency Hopping 1 1-5 5-10 10-20 50-100 1 Pulse repetition interval (μs) 1428 150-230 250-500 250-500 1000-5000 333 for DFS approval are required to apply for removal of this band by July 2007. Furthermore, changes have recently been made to the DFS testing requirements. Specifically, the FCC now requires full testing of all bandwidths. These changes, and other changes that may follow, will pose additional challenges to manufacturers of devices affected by the new DFS standards. That is why our final words of advice are to remain informed and be prepared for additional changes to the FCC’s DFS testing requirements. Conclusion In closing, we hope that the information and advice we have provided here is useful in helping wireless device manufacturers meet the challenges posed by the FCC’s new DFS requirements. We have found that manufacturers who prepare themselves properly and allow sufficient time for this process generally have little or no problem meeting the DFS requirements without significant impact on their product release process. However, manufacturers who fail to prepare properly, or who come into the process with unrealistic expectations about the time requirements and challenges associated with the DFS testing and certification process are generally disappointed in the end. We urge all manufacturers affected by these requirements to take the time to educate themselves and prepare accordingly. Like it or not, DFS is here to stay. Juan Martinez is a Senior Wireless Engineer and Tom Wetzel is Executive Director of Sales & Marketing at Elliott Laboratories. They can be reached at info@elliottlabs.com. FAST Link www.conformity.com/0950 Pulses per burst 18 23-29 16-18 12-16 1-3 9 pulses per hop, 100 hops per burst Pulse Modulation None None None None 5-20 MHz linear chirp 333 Hz Hopping Rate n/a n/a n/a n/a n/a Note: The bin 5 waveform is to be made of between 8 and 20 bursts over a 12 second period. Each burst contains one, two or three pulses. Each pulse within a burst has the same modulation and width but the repetition interval (for the three-pulse burst) can be different between the first and second, and second and third pulses). The parameters for the pulses in different bursts are not identical. Table 2: FCC Radar Waveforms 34 Conformity September 2007 http://www.conformity.com/0950

Table of Contents Feed for the Digital Edition of Conformity Magazine - September 2007

Contents Editor’s Note FCC Extends Disability Access Requirements to VOIP Commission Fines Importer $3 Million Over Non-Compliant TVs FCC Gets Tough on Retailers Over Analog TV Tuner Labeling Analog Cellular Service Sunset Date Reaffirmed Commission Adopts Recommendations of Katrina Panel Free-Space Antenna Factors Through the Use of Time-Domain Signal Processing Editorial Correction ESD Open Forum An Update on Revisions to IEC 61000-4-2, the Basic Standard on ESD Practical Advice for Meeting the DFS Testing Requirements of the FCC The EMC Impact of Embedded Software ESD Design Buyer's Guide Tate Renominated to the FCC EPA Releases Report on U.S. Electronic Waste Additional Standards For The EU’s Toy Directive Medical Device Manufacturer Enters Consent Order Updated Guidance Document on Laser Products Issued FDA Offers Advice on Defective Heating Pads CPSC Issues China Product Safety Program Report Other CPSC Actions In The News IEC Standards Update Product Reviews Product News UL Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - September 2007

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