WI-Fi, Blue Tooth, 3G/4G, GPS, NFC - What's it All Mean?

This array of communication technologies can be confusing but the basic idea is quite simple. These are all members of the family of Electromagnetic Waves. Other members of this family include

• TV and radio signals
• Microwaves in your oven
• X-rays
• Gamma rays (from radioactive decay)
• Ultraviolet and Infrared rays
• And the ever popular visible light rays in a variety of colors that surround us every day

The only difference in these waves is their frequency. If you could change the frequency of light rays, they might become microwaves and you'd be cooked like a hamburger when you turned on a lamp to read.

To communicate using electromagnetic radiation we have created devices like radio and TV transmitters coupled with sending and receiving antennas so we can hear or view the signals. Our antennas pick up all the signals and the tuner in a radio or TV set picks out a very precise frequency - 91.1 for example - so we hear a specific station.

Our cell phones have the capability to communicate using the parts of the spectrum listed in the title above. There is an antenna built into your cell phone for each type of signal it can handle. Obviously the 3G phone signal coming from a cell tower is included or it wouldn't be a cell phone. 3G means the third generation cell phone technology; 4G is coming soon. 3G and 4G signals are designed primarily for voice transmission but can be used for data if you don't have a wi-fi connection available. The other signals are designed for data but services like Skype allow voice signals to be be handled also.

Wi-fi signals are generated by a wi-fi router in your home, office, coffee shop or collection of devices in a city-wide system. 3G signals can be transmitted for miles but your wi-fi router only has a range of a few hundred feet. Your neighbor may be able to pickup your signal and use your Internet connection if she is in the right part of her house. Most modern cell phones can receive GPS signals from satellites eleven thousand miles above the earth (see "range" below). The GPS signal is not related to the 3G signals so a cellphone connection is not required.

Bluetooth signals are short range signals used so nearby devices such as a keyboard and computer or cell phone and ear piece can communicate. Even shorter range signals will be used by NFC - Near Field Communication system - being developed now for credit card applications. That signal can only be transmitted for an inch and a half; very low power indeed. Every signal differs from all others in two respects - frequency and amplitude (power).

The range a signal can travel is determined by its power - also referred to as amplitude. There are strict regulations on what frequency and amplitude someone can use to broadcast or transmit. A certain frequency can be used in one location by one radio station. That same frequency can be used in another distant city provided the strength of the signals are set so they don't extend into each others territories.

An entirely new system consisting of thousands of high-powered wi-fi towers is under development by LightSquared. These towers would blanket the US with high powered wi-fi signals for nearly universal Internet access across the country. There is controversy, however, because these wi-fi signals are very close to the frequencies assigned to GPS. and could interfere with navigation. This could be very serious since airline navigation systems are at long last being converted to GPS.

The Dark Side of the digital age

Many of us take more photos on a long weekend than we did the entire time we used film cameras. Arguably the quality is improved based on immediate feedback and numerous retakes. We also avoid finding out when our film is developed - and our vacation is over - that an entire roll was poorly exposed due to unusual lighting conditions or an improper camera setting. All in all we feel like we've solved one of the world's greatest problems - documenting our lives for future generations. After all we repeatedly view, sort and arrange those precious pictures taken a century ago. We hang them on the wall and proudly point to great-uncle Eggbert as we relate our family's illustrious or not-so illustrious history. But there is a looming downside to the digital age and it affects much more than our photo libraries.

I'm often ask about the best way to store/archive photos and other files for the long term and I give the same simplistic answers as every other "expert" - make copies on CDs, store them off-site, etc., etc. But the very serious problem of long term storage of files of all types was discussed recently in Computerworld and here is a hint of the problem.

The Domesday book - a detailed property ownership survey in England commissioned by William the Conqueror - was published in 1086. It was recorded on sheepskin and written in Latin. In 1986 an updated version was prepared using the latest technology - laser discs. Guess which one was readable fifteen years later - assuming you or a friend could read Latin. That's right, the 935 year old book could be read but the "modern version" could not because the laser disc players and software were obsolete. Reading the 1986 version required significant custom hardware and software engineering.

Reading at least part of the the article by Lamont Wood is informative. Organizations with substantial concerns include the Library of Congress, the National Archives and the U.S. Geological Survey and you can forget about gigabytes; they talk in terabytes and petabytes (one thousand and one million gigabytes respectively.) The problem is reminiscent of the Year 2000 Problem but this one will not be over in five years. Digital data has the potential to last literally forever - it's all just collections of zeros and ones - providing archiving strategies are developed to store those quadrillions (petabytes) of bits.

Is DC culture changing with the times?

According to a recent article in the Washington Post "To do business with the feds, BlackBerrys are not preferred; they are often required. To my knowledge, I don't have contracts that require I get an iPhone for an employee," said Frank Smith, chief information officer for McLean consulting giant Booz Allen Hamilton. "I do have contracts that stipulate BlackBerrys." ... But people [including] app developers, telecommunications companies and even the chief technology officer of the United States -- think change is coming..." Read the complete story.