WiFi Data Systems: What to Watch Out For (Part 5 of 5)

Using wireless modems is an appealing way to build a data network because it's convenient. Long cable runs aren't necessary, which tends to keep the labor costs down. Modems are inexpensive and can be obtained easily. Expansion of the network can be as simple as buying another modem box and locating it where it's needed.

However, despite all the advantages, there are a few land mines that one can hit when deploying a wireless network. In fairness, it should be noted that the problems listed below are rare and very few networks will have these issues. But, such problems have been known to arise and it's worthwhile to keep them in mind. Especially, if a network develops a problem that needs troubleshooting after it's been deployed.

LICENSED AND UNLICENSED USAGE

First, I should clarify something about the legal aspects of anything that uses radio waves. In a broad sense, radio (or wireless) devices fall into two classes; those that require the user to obtain a license from the Federal Communication Commission (FCC), and those that don't.

The FCC issues licenses to users for their radio communications equipment. This includes everyone from police and fire departments to radio and television stations. Without a license, those organizations can't use their radio equipment. However, when WiFi and wireless computer networks began to be deployed in increasing numbers, it became obvious that trying to issue licenses to everyone who wanted a local network just wouldn't be practical. There were just too many users.

So, the Commission set up various bands that users could access with unlicensed devices. They also put the burden on manufacturers to insure that the equipment they were making for use in these bands met the certain technical specifications. All products that are made to be used in these bands must comply with Part 15 of the FCC rules.

The good news here is that when you purchase a new wireless modem for your computer network, you don't have to worry about getting a license to use it. All you have to do is plug it in and let it work.

Except there is one downside to this: the possibility of interference.

INTERFERENCE FROM OUTSIDE SOURCES

The bands used for wireless data communications for unlicensed users are the 2.4 GHz and 5.8 GHz bands. Because of the proliferating usage of radio frequency based systems today, it is possible for some non-WiFi devices, such as cordless phones, to create a problem for a wireless network.

In essence, there are two main criteria that Part 15 of the FCC rules lays down. First, any unlicensed device used in these bands must not cause interference with a licensed device. Second, any unlicensed device must accept interference that is caused to it.

In the first instance, if your wireless network is causing interference to a licensed users, then you have no choice but to correct the problem immediately or, worst case, shut down your network. The user with the license has the priority and the right to the usage of the band in question.

In the second case, if a user has a device that is causing you trouble and that user has a valid FCC license, then, bluntly put, you are probably out of luck. You can't force a licensed user to stop using their devices or equipment. Again, this is because the user with the license has the priority.

There are other technical issues that also need to be taken into account when one of these situations arise, but those are generally ones that you may hit with outside interference. That is, when something other than a wireless LAN interferes with another wireless LAN.

INTERFERENCE FROM INSIDE SOURCES

Under certain conditions, it is possible for a data network to interfere with another data network. This is extremely rare, but as anyone who has worked with radio equipment will testify, almost anything is possible.

If you have an existing wireless network deployed and you want to add another network, you might experience this issue. Even with all of the modern software and sophisticated modulation techniques, it can still happen. Many times the instruction books provided with wireless modems will discuss this and will suggest some ways to keep the two networks from colliding with each other. Difficult cases may require you to obtain the help of a competent radio engineer to overcome the problem.

A more difficult challenge is when your network is interfering with another user in your area, say a next-door business or neighbor. You'll have to then work with them to fix the problem. However, because of the low power levels used in wireless networks, it's unlikely you'll ever have to deal with this issue.

Some users, in an effort to cover more area, will attach a different antenna to the wireless modem than the one that came with it. Some cordless phone system users will try this too. But, the FCC publication "OET Bulletin No. 63" explains the need of using the proper antenna as follows:

"...Part 15 transmitters must have permanently attached antennas, or detachable antennas with unique connectors. A "unique connector" is one that is not of a standard type found in electronic supply stores.

It is recognized that suppliers of Part 15 transmitters often want their customers to be able to replace an antenna if it should break. With this in mind, Part 15 allows transmitters to be designed so that the user can replace a broken antenna. When this is done, the replacement antenna must be electrically identical to the antenna that was used to obtain FCC authorization for the transmitter."

So, if you want to try to make your system cover more territory, it's better to use a "booster" or get another modem. Changing an antenna could create more problems for you than you want.

PROBLEMS WITH THE PHYSICAL ENVIRONMENT

Part 4 of this series discussed the problems that can happen due to the building that you're in. Things like large steel beams used in the framework or large quantities of concrete in walls or slabs dividing sections of a building can block signals from covering all the areas that need to be served. Again, a good radio engineer is the best person to help solve problems caused by the structure that the network is deployed into.

HACKERS, INVADERS AND SPOOFERS

Also in Part 4 of this series, we discussed the security issues involved in over-the-air networks as opposed to wired networks. This is a real problem and needs to be considered if you're going to go wireless. Don't assume you'll be alright and that you won't need to protect the network. Use the proper recommended security techniques.

FINAL THOUGHTS

I hope that this Wi-Fi Series have been helpful in understanding radio, wireless, radio frequency information and the use of over-the-air data transmissions. The main goal of this series was to make it clear that the hardware and software requirements are very complex. Sometimes it may seem like magic, but it's really not. It takes a lot of work on part of both the hardware and software engineers to make our data modems work as well as they do. Even so, future developments will probably be even more astounding than what we have today. That's the beauty of living in a high technology world. 

Click here to revisit any of the the posts you may have missed in this series:

Part 1 - WiFi: What Does the Name Mean and How Does it Work? 

Part 2 - The History of Wireless Technology: Wireless or Radio? 

Part 3 - WiFi Radios and Modulation Techniques 

Part 4 - WiFi RF and Data Security Issues

Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com. 

WiFi RF and Data Security Issues (Part 4 of 5)

The use of radio-frequency (RF) devices for wireless transmission of data is an appealing way to set up local networks (LAN). RF-based routers have become relatively inexpensive, easily available from many suppliers, and simple to implement.

In places like private homes, small business locations and even larger areas, such as malls and hotels, wireless networks have become about as common as telephones. Retailers, especially those that operate large brick-and-mortar stores (ie supermarkets or department stores) frequently set up these networks. Consumers who walk into a store are urged to sign-on and thereby get special prices or get help navigating through the store. 

In the last decade or so, many businesses that exist in an office environment, like insurance companies, have implemented wireless LANs, both for their employees and also for use by visitors. However, there are some potential problems for both the operator of the network and the users of the network.

RF SIGNAL BLOCKAGE ISSUES

Unfortunately, radio waves can't go through all materials. Metallic items used in most commercial construction, like metal wall studs, window frames and HVAC ducts, can act as signal shields. These items can also deflect signals around in ways that make I hard for mobile devices, like laptops and smartphones, to receive the signals. This can result in some areas being inaccessible to any over-the-air connection.

Not only does this make it hard for the mobile devices to receive the signal from the LAN, it can make it equally hard for the LAN to "hear" the mobile device. Data sent from the mobile device, either doesn't get through or it requires so many retries due to dropped packets that the response time is slowed down dramatically. The result is frustration on the part of the users.

SCRAMBLED DATA / INTERFERENCE

Two of the more frustrating experiences users suffer are problems with data being scrambled and other services that use the wireless bands creating interference (almost always unintentionally).

As previously mentioned, it can take many retries to send or receive the information. Besides slowing down response time, the data can get badly corrupted. This can result in problems like missing or garbled text, images and graphics not loading, and other unwanted effects.

Interference to a LAN signal these days is rare, thanks to modern modulation methods and encoding/encryption techniques. But it does happen occasionally. Wireless LANs typically use the unlicensed sections of the Industrial, Scientific and Medical bands (also called ISM bands for short). Many other services use these bands also.

Because the Federal Communication Commission does not issue licenses to users to operate in these bands, there is no protection to any individual user against invasion from unwanted signals.

HACK ATTACKS

By far the largest drawback, and the most dangerous one, is the ability of "wide open" networks to be invaded by hackers. Attacks of this type are very common. Criminal hackers can extract everything from documents to credit card and banking information stored on mobiles. The rise of identity theft is due in part to this kind of activity.

SOLUTIONS

Wireless data LANs that operate in the ISM bands must use a fixed power level. It's not possible to increase the actual transmitted power. Federal Communications Commission (FCC) rules prohibit changing this. Increasing the power to improve coverage is not an option.

However, much work and research has been done by the hardware manufacturers in the area of antenna technology. If you look at a modern router, you'll probably see at least two, or as many as eight, antennas attached to it. This helps a great deal with coverage. Routers from the major makers, such as Linksys or Netgear, now have much longer ranges and larger areas of coverage than those of just a few years ago.

In some environments, areas to be covered and materials used in the construction mean that one single router can't cover the entire area. It is possible to deploy another router, but many times a wireless range extender device will provide signal where it's needed.These devices are simple to install and relatively inexpensive compared to the cost of a router. They are used extensively in both commercial and residential locations. 

Proper placement of both the router and any range extenders can help a lot in improving coverage. Avoiding putting these devices near large metallic objects, or anywhere a large number of electrical cables are installed, can help to insure that signal quality is the best it can be.

By creating proper hardware placement, the number of dropouts and the need for continuous retries to get data delivered successfully can be reduced to a much more tolerable level. This can also help alleviate interference from other users in the band. 

The problem of hackers invading a LAN, particularly one that is open and not secured, will always be with us. In an employee-usage environment, like in an office, or in a home where the LAN is used by only one family, proper security methods typically eliminate attempts by hackers to compromise the network. If visitors need access, they can be given a temporary password that will allow use of the wireless LAN for a limited time.

From the user standpoint, another way to insure that a mobile device can communicate securely in an open-network environment is to set up a Virtual Private Network (VPN). This creates a tunnel from the user to the website or server that is being accessed and is encrypted to keep data from being interrupted. There are many companies that offer this service for a monthly fee.

Now the concern is; what are the pros and cons of deploying a wireless network in any given environment? Our next, and final post in this series, will define some of these and point out the good, the bad and the ugly sides of wireless LANs.

Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com. 

WiFi Radios and Modulation Techniques (Part 3 of 5)

As mentioned in our History of Wireless Technology post, getting data sent over the air without wires isn't as easy as it is when you have a wired, or cabled, connection system. 

Think about a standard two-way radio. The correct name for this kind of radio is a "transceiver". It both transmits and receives, therefore it's called a "transceiver". 

It's probably safe to say that most people know at least something about how a radio like this works. If you've ever watched a television show that feature police, fire, or other people that use two-way radios, like airline pilots, you've seen these radios in use. When you want to talk, you pick up the microphone and push the button on the microphone. When you're done talking, you let up on the button. The person you're talking to will then reply to you and you can hear them.

Unfortunately, for data communications, trying to use radios in this manner won't work. This doesn't begin to allow data to be sent and received with the speed, accuracy and reliability that is needed.

SPEED AND BANDWIDTH NEEDS

Radios used for data have to be fast, with lots of bandwidth, and be reasonably immune to natural and man-made noise and interference. They also have to be able to accept data streams in various protocols and translate the digital data (the ones and zeros, if you will) into something that can be impressed upon a radio signal. Following that, the signal has to be of a high enough quality that it can be received and turned back into the original data (again, the ones and zeros).

The proper word for putting any information onto a radio wave is called "modulation". We don't have time here to delve deeply into all the math and theory involved to explain the way digital data is modulated into a radio wave. However, we will look at the main method used for LANs, WANs, mobile cellular phones and data communication in general.

The modulation technique that's almost always used is a method called "spread spectrum". It's got an interesting history. Spread spectrum was developed for use in military communications. The idea was to keep the enemy from being able to intercept and decode secret communications, yet also make it hard for the enemy to jam radio signals. 

The original spreading technique was called "frequency hopper", or it's more modern term, Frequency Hopping Spread Spectrum (FHSS). It worked by actually changing the frequencies as it was transmitting the signals. Every few milliseconds, the transmitter would hop to a new frequency. So, even if you could tune into one of the frequencies in use, it wasn't long before it was gone. Then, on the other end, the receiver had to be able to follow the transmitter when it changed. This took a lot of careful timing and delicate control, but it did work. It kept the enemy from being able to intercept the communications.

Frequency Hopping Spread Spectrum (FHSS)

The first patent for this type of modulation was issued in 1942 to music composer George Antheil and Hollywood actress Hedy Lamarr. The two were introduced at a party where they originally bonded over the women's magazine articles Antheil wrote about endocrinology and ways to increase Lamarr's bust size to make her more attractive in Hollywood. But it was during these scientific discussions that they turned their conversations over to the war and how the Germans were struggling with their torpedoes missing their targets. This is rather a fascinating story as told in a previous blog post, Beauty, Brains and Secret Communication, or if you're a podcast listener, check out the You Must Remember This episode featuring Hedy Lamarr.

For many years, the frequency hopping communication system was classified as "SECRET" by the United States government. The Army Signal Corps was the only organization that used it or knew all of the details on how it worked. As time passed, however, researchers in the private sector began discovering how spread spectrum functioned. When the scientists and engineers outside of the military figured out the secret, it wasn't really a secret anymore. Finally, after the patent expired in 1962, it was declassified and available for use by the civilian sector.

MORE THAN ONE WAY TO HIDE THE SIGNAL

In addition to the original Frequency Hopping Spread Spectrum (FHSS), the other spread spectrum system is the Direct Sequence Spread Spectrum, or DSSS for short. This works differently, as it doesn't "hop". DSSS takes the digital signal and combines it with the radio signal in such a way that the signal is spread out over a large number of adjacent frequencies, at the same time.

Direct Sequence Spread Spectrum (DSSS)

There are several ways to do this, but one of the more common spreading methods is called Code Division Multiple Access, or CDMA. Almost all mobile phones used in the United States operate using this method. Among its many advantages, it allows a high level of security for phone calls to help eliminate eavesdropping on phone conversations. It also allows several mobile cell phone calls to exist in the same general frequency band at the same time. By allowing that, more mobiles can be used by more people without the problem of running out of available channels, which was a common issue in the early days of mobile cell phones.

It also helps in allowing what is called "duplex" communications. This means that you don't have to push a button to talk, like you do with the two-way radios as described in those previously mentioned tv shows about police and firemen. This makes a mobile cell phone call sound and function almost the same as a regular landline telephone call.

THE NEW AGE OF DATA COMMUNICATIONS

With the development of the capabilities described above, mobile phones and data communications entered a new era. Now, there are ways to create radio-based systems that emulate a cabled system. The age of the wireless router came about as a result of these advancements in radio-frequency systems. However, despite all of the wonderful capabilities we now have, there are still some pitfalls, land mines and other difficulties that a radio/wireless data communication system is subject to. In our next installment, we'll explore some of the what-not-to-do's.

If you'd like to read more on all of this, plus more that we didn't cover here, I recommend reading "Wireless Communications and Networks", by Dr. William Stallings. It's very easy to read and makes all of the theories very understandable.

Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com. 

The History of Wireless Technology: Wireless or Radio? (Part 2 of 5)

Back in the latter half of the nineteenth century, uses for electricity were just being discovered. By 1880, Thomas Edison had improved his original light bulb to the point that it was a viable product, and early wiring of cities for power had begun. But scientists were discovering that there was a lot more to this new source of energy than first appeared.

In 1888, at the University of Karlsruhe in Germany, a young professor named Heinrich Hertz, proved what other scientists had only suspected; you could send electric "waves" through the air.

However, there hadn't been much work on the practical use of these waves at that point. So, the scientific and technical community just called them "Hertzian waves", since Hertz was the first to prove their existence. But it wasn't long before experimenters were looking at ways of using these new "waves" to do some useful work.

The wired telegraph had been around for a long time. In the United States, Samuel Morse created the first useful wired telegraph as early as 1844. Of course, to make it work, you had to string wires. That was time-consuming and expensive.

Some of the early pioneers of electrical science got the idea that maybe they could get rid of the wires by using these "waves" Hertz had already proven existed to send telegraph code instead. The scientific term that describes the sending of the waves is "radiation". You are "radiating" electricity when you create and send the waves. Once you do that, you have to have a way to "hear" them. The human ear can't hear these waves, so it was necessary to build something to do this. 

In 1890, Edouard Branly, a French physicist, developed a device that would do just that. He called it a "radio-conductuer", since it could receive waves that were being "radiated". However, not everyone used "radiation" or "radio" when discussing this new form of communication.

Gugelielmo Marconi, working in England between 1896 and 1898, showed that you could send signals through the air at considerable distances, and you could send Morse code on these signals.

Marconi called the company that he founded "The Wireless Telegraph and Signal Company" to make sure everyone knew that you didn't need any wires to send Morse code by this method. So, "wireless" became a common term for this new form of communication in England.

However, some technical people began to gravitate more towards using the term "radio" in place of the term "wireless". In the January 21, 1898 issue of The Electrician (London), a letter from a reader suggested that the term "radio-telegraphy" might be preferable to "wireless-telegraphy". 

In 1904, the British Post Office, which was the branch of the government that sent telegrams, specified that any telegram sent by an over-the-air method had to insure that "...the word "Radio"... is send in the Service Instructions". 

Meanwhile, in 1906, in Berlin, Germany, the Berlin Radiotelegraph Convention included a Service Regulation specifying that "Radiotelegrams shall show in the preamble that the service is 'Radio'", again to distinguish it from the use of wired telegraphs.

There were some holdouts on this, however. Electrical engineer William Maver, Jr., who, in the preface to his 1910 book "Wireless Telegraphy and Telephony", said that he intended to stay with the older term "wireless". Apparently, he was a traditionalist.

Between 1907 and 1920, "radio" and "wireless" were used to describe the new communication method interchangeably. In the United States, Lee de Forest, an early researcher who is credited with developing some of the first tubes used in receivers, called it "radio". This led to a general migration to the term "radio" in the United States. However, in England and Europe, "wireless" was still widely used.

It wasn't until the early years of broadcasting, around 1920, that the term "radio" began to become the more common term used everywhere. In 1923, the British Broadcasting Company (BBC) launched it's magazine devoted to broadcasting, called "Radio Times" (still in publication today). The BBC's decision to use "radio" pretty much put "wireless" aside. In most places around the world, "radios" became an understood term for over-the-air broadcasting and communications.

That is, until the rise of computer networks in the latter half of the 20th century.

Just like the early telegraph signals that were sent in the nineteenth century, early computer networking was done using wires, or, more properly, cables. Many times, the choice of cabling was either a coaxial cable or a twisted-pair cable. (Today, the bulk of the wired networking is done with twisted-pair cables.)

As computer networking evolved, it was easy to see that the need for over-the-air, un-cabled networks would provide a lot of convenience and solve a lot of problems. Just like what happened in the early 1900's with Morse code communications, scientists and technologists knew that, somehow, a way would be found to get rid of the cables.

Some early over-the-air computer communications with microwave systems was successful, due to the wide-band capability of these systems. Because of the bandwidth available at the higher microwave frequencies, these systems could transmit a large amount of data at a fast rate. Satellites, too, had this advantage due to the frequencies at which they operate. Uplinks and downlinks could replace terrestrial cable systems, including those that ran under oceans.

Finally, regulatory agencies created radio bands which were originally intended for use in "Industrial, Scientific and Medical" research, appropriately called ISM bands. Hardware designed to operate in these bands did not require users to obtain licenses. This opened the door to allow unwired computer networking systems to be implanted without users having to comply with complex regulatory filings.

And so, as these systems became more common, the term "wireless" arose again, due mainly to the fact that the use of these bands allowed elimination of the wires (or again, more properly, cables) needed to tie computer systems together.

So, now we're back to defining these systems as "wireless", just like in the early part of the last century. To quote baseball's Yogi Berra, "It's déjà vu, all over again".

Interestingly enough, today one major technical group defines wireless networking as: "Using radio, microwaves, etc. as opposed to cables to transmit computer networking signals". 

"Wireless" or "radio", the term used is less important than the ability to perform the work needed to get data across given distances. Call it what you will, it has revolutionized our ability to connect computers into a network and contributed greatly to the rise of the world-wide web.

Timeline: Radio vs Wireless

In part 3 of our series, we'll look at some of the requirements necessary to make radio/wireless systems capable of sending and receiving data without interfering with each other, as well as touch on the software systems that create these results.

Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com. 

ROAD REPORT: Space...the Wireless Frontier

Ok...time to get out your Star Trek communicator pin, your Mr. Spock ears and Klingon mask and sash. Clear-Com brings us to the edge of space exploration - or at least to the training centers.

We start with a 6 million gallon pool that's bigger than a football field. A major space agency uses this pool to train astronauts from around the world, simulating the weightless conditions of working in low earth orbit.

The astronaut trainees put on their space suits and, through an umbilical of tubes and cables to the poolside tender positions, get their air, medical telemetry and communication needs. They all connect via standard 4-wire connections (line-level inputs and outputs to a matrix port in the main control server room). There are controllers at poolside and controllers simulating Mission Control Center-like consoles that guide the trainees and the scuba diver assistants through the paces of their exercises. A beautiful techno-ballet in the slow motion world of the underwater, weightlessness of simulation training.

Why Do Astronauts Use Training Pools?


Imagine you are all suited up in your cool, high-tech space suit. HAL900 has opened the Pod Bay door. You stand on the step, taking in the unbelievable view and....you step off into the abyss to do your spacewalk in order to fix an antenna on the other side of the Space Station. In the weightlessness of space, you turn your wrench to tighten the bolt on the antenna. But, if you haven't practiced your task while weightless, just as you move your body to turn the bolt....it's quite possible you might also turn the whole Space Station! Didn't know your own strength, did you?

Well, this training is why the astronauts do simulation training at the pool. Using Clear-Com's FreeSpeak II wireless and Eclipse HX digital matrix systems, the team is able to coordinate communications between the Control Room simulations, the Dive Boss' station, the medical team (who constantly monitor the astronauts' and assistant divers' vitals), and the technical coordinators, while maintaining clear and open lines of communications. This way, the task of learning how to work in weightless conditions can be run in a smooth, efficient and safe manner. 

Wireless Work Flow

Wireless communication can be very persnickety, as we all know. In this decade, we are seeing the loss of wide swaths of the narrow UHF spectrum. As these bands are sold off to the highest bidder, we are all left looking for new places to use our small signals for mics, comms and IFB (interruptible fold back for talent and in-ear monitors). 

Clear-Com's FreeSpeak II plays a big part in the workflow here. First off, the 1.9 GHz model keeps the comms well out of the way of other frequency traffic, both in the remaining UHF and the now very crowded 2.4 GHz spectrum. With that said, with the deployment of Frequency Hopping Spread Spectrum (FHSS) technology and recent Clear-Com innovations, the use of 2.4 GHz wireless systems are becoming more attractive. The FreeSpeak II 2.4 GHz has been chosen for some of these training facilities because of the redundancy transmission of the FHSS scheme, which helps with the immensity of the room and reflective nature of the architecture and the huge water surface reflectiveness. 

The FreeSpeak II solution uses a deployment of an array of Transceiver Antennas that can service up to 5 beltpacks per transceiver. These are then spread out around the needed coverage area and the beltpacks hand-off from one antenna to another as the users move about the covered areas. Their seamless hand-off is clean and has a killer clear sound. The high quality spectrum of audio makes the FreeSpeak the best sounding multi-channel communication system around. And when using the matrix integration card option, as the large training pool area has, it makes it possible for any intercom panel in the facility to directly talk with any and every beltpack user, and vice versa. When programming the FreeSpeak II through the Eclipse HX's EHX software, it's just a simple drag and drop function. BINGO...you're all set to get to work. When using this integrated method, the beltpacks can do just about anything that the wired matrix user panels can do. If there's a telephone interface in the matrix, the FreeSpeak II beltpacks can be programmed to make a telephone call (including speed dial to the actual destination phone number) or trigger relays or GPI's with the touch of a button.


The award-winning audio clarity of the FreeSpeak II wireless system makes for crisp and clear communications, in an environment where it's most vital, like simulated training courses for astronauts going into space. These expert technicians need a system that can adapt to their unique workflow and one that they can trust will work in any environment. Perhaps, one day......even in space. 

Rom Rosenblum has always been a capable, yet rebellious audio-guy. Originally in the music recording business as an engineer, with a long Emmy Award winning career in live TV broadcasting, Rom worships at the altar of All Things Audio. As one of the Applications Engineers at Clear-Com, he works as a catch-all fixer for folks who need tech support, commissioning, systems design, product development, and sales support.

Wi-Fi: What Does the Name Mean and How Does it Work? (Part 1 of 5)

WHAT IS Wi-Fi? 

Unless you've spent the last few years inhabiting a cave, you've probably heard the term "Wi-Fi" (or maybe "WiFi", which is an alternate spelling). It's become one of those common "buzzword" expressions, like "cellular", or "mobile", or "social media".

But just exactly how do we define Wi-Fi? We all know what its most basic use is; it allows us to connect to the Internet without having to plug a cable into whatever we're using to connect. 

What the name actually means, where it came from, and how the technology works are things that many people don't fully understand. What we hope to achieve in this series of posts is some enlightenment on these subjects.

Wi-Fi IS NOT AN ACRONYM

The original standard for all wireless capability was developed from the Institute of Electrical and Electronics Engineers, or IEEE, and was originally published in 1999. The full-blown name for the important part of this standard is "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications".

As time went by, it became obvious that there were certain products that wouldn't work with other products. Many times this was because the wireless modem in one device worked differently than the one in the device that it was trying to connect to. This was due to the face that the IEEE had no way to test different manufactures' equipment for compliance with the standards it had published.

So, thus was created a non-profit organization called the Wireless Ethernet Compatibility Alliance. It was formed to help ensure that wireless Internet products conform to certain interoperability standards. The idea was to make certain that one company's "box" could talk to another company's "box". 

However, after the Alliance had been in existence for a while, a non-technical issue arose. This was that the name of both the Alliance, and the standard, were considered too long and too clumsy.

Some thought was given to using the initials, WECA, a shortened version of the Alliance's name, but that was only part of the problem.

The bigger problem was that the standard's name had become known as the "IEEE 802.11b Direct Sequence". As one founding member of the Alliance commented, "We needed something a little catchier than that". The name just didn't have that "ring" to it to make it memorable. 

So, the Alliance hired a consulting company, called Interbrand, to help them come up with something that was more memorable, and would still be descriptive enough to explain the standard, and the work that the committee was doing. 

The result was the term "Wi-Fi", and the new name for the Wireless Ethernet Compatibility Alliance became the Wi-Fi Alliance. Although some members of the Alliance were not sure that this was a good idea, since the name didn't have a specific literal explanation, the consensus was that this satisfied all the requirements. It was easy to spell, easy to remember, and had the potential to become one of the "buzzwords" that populate our conversations today.

NOW THAT WE'VE NAMED IT, HOW DOES IT WORK?

Because of the speed, reliability, and usefulness of Wi-Fi, we sometimes forget there is a single most basic concept to it; a radio frequency signal. (If you're familiar with the OSI computer networking model, this is the "physical layer")

When you get on the other side of all the software, the protocols, the modulation techniques and all the other stuff involved in Wi-Fi, you can boil the whole thing down to the fact that Wi-Fi consists of a series of computer-controlled two-way radios. That might sound almost too simple, but really, within the laws of physics, that's all there is.

Of course, some people will balk at the term "radio" and insist that non-wired data communications should be referred to as "wireless". For right now, just keep in mind that radio waves being sent through the air from one device to another are what allows information to be transferred in a Wi-Fi environment.

Since the real purpose of Wi-Fi was to provide a way to transfer the same type of information that can be sent through a wired network, such as a 100BASE-T Ethernet network, some challenges faced the early developers. 

First off, all the protocols, control codes, and other metadata that a wired network uses had to be put onto the radio signals. Also, all this information had to flow in both directions, that is, to and from each network node. When you include the data itself, this means sending and receiving a lot of information.

In a wired environment, you don't have to constantly turn on and off the radio waves in the devices. With radio communications, this usually has to be done because two radio waves on the same frequency, at the same time, will interfere with each other.

Trouble is, this can be very time-consuming. It can slow data transfer down significantly. In data communications, speed is of the essence.

So, how do you overcome this challenge? What can you do to a radio wave to make it work compatibly with other radio waves right next to it, all around it, or even on its very own frequency?

In Part 2 of our series, we'll explore some of the ways to overcome these issues, and take a look at the history and definitions of the words "wireless" and "radio".

Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com. 

Emil Leon Matignon

On April 8th, Clear-Com mourned the loss of  a highly regarded audio engineer, musician, inventor, salesman, and friend - yesterday would have been his 61st birthday. In his 35 years with Clear-Com, he gained much respect from his customers and his colleagues. Here are just a few parting words from those of us at Clear-Com.

Emil Matignon – An Appreciation

By Bob Boster, Clear-Com President              

When I first came to Clear-Com in 2006 as a sales guy I was assigned to sit next to Emil for the first week to learn the products from a system design standpoint and get a feeling for how the business flow worked by listening in on his phone calls.  At that point Emil was doing a split of technical support, sales support, and order entry.  It was a great chance for me to learn the Clear-Com way.

As a former user I had already known a decent amount about how partyline worked overall, but there are some obscure elements that Emil was an excellent teacher on and I felt gratified when he said I was his fastest student to ever pick up on those things (IFB, two-radio interfacing, camera CCU’s). Over the years he would remind me of that and I still feel proud that he called that out.

Emil was a great example of our dedication to customer service and he embodied the Clear-Com focus on making sure we address our customers’ needs personally, with passion, and deep knowledge of how the product is used.  Emil’s example in this regard was not unique, but it certainly was a shining one – everyone who ever worked with him felt that and will carry that example with them into the future.

He was gregarious, inquisitive, sensitive, and full of energizing stories about his various adventures, both professional and otherwise. Over the years Emil was challenged to keep up with our innovations and one of his special qualities was he was as excited to learn something new from his colleagues as he was about teaching them something they might not know yet.  With an eye to the past, Emil was still working on making sure he could take care of business in the present and even looking into the future.

While I personally will miss the sound of his voice coming over the cubicle walls saying ’how’s it going, bud?’ I also know we have done an excellent job in allowing Emil’s example to impact our current support staff and we will strive to make sure our customers are just as passionately supported as they ever were.  Please join me in honoring the passing of a lion of the intercom world.

By Peter Giddings, Clear-Com Vice President of Global Events

Today I was saddened to hear of my dear friend -- in fact, everyone's friend, Emil Matignon's passing. It seems like only yesterday (in fact, some 30 years ago) when our new recruit, Emil, attended his very first NAB. How keen and excited he was to learn from me everything he could about Clear-Com. As the years rolled by, Emil became Clear-Com's "go-to" guy, particularly in so far as partyline was concerned. Came the day when Emil's heart condition became so challenging that he was relegated to the home office, but whilst his heart occasionally did, Emil himself never missed a beat. At our next NAB, we were literally inundated with Emil's global friends, demanding to meet, and thank him for his support.

I have never, before or since, experienced anything like it.

In all of the past decades, I cannot recollect a single day when Emil was less than his always ebullient self. As our friendship grew, we also had music (at an earlier time I played double bass) in common, it pained me that eventually Emil, having initially dabbled at drumming, subsequently performed on his electric bass. A bear hug from Emil upon returning from my business travels, many of these trips taking 5, or even 6, weeks in length, always heralded his desire to vicariously live through me my adventures .... experiences that clearly he would no longer be able to have himself.

I can now clearly see Emil in Eden.Healthy again, with that irresistible ear to ear grin, trading riffs with admiring Charlie Mingus, Yaco Pastorius, John Entwhistle, Ray Brown, and Jethro Tull .

Rest in peace my friend, leavened with some solid grooving.

By Ed Fitzgerald, Clear-Com Director of Customer Satisfaction

Emil was a loving member of our extended Clear-Com family. Customer service savvy, always ready with insightful answers, a smile in his voice and never too busy to help, Emil was the perfect example of how it's done. Never known to give up, he was the customer's best friend. Our family is richer for having known Emil and we will miss his infectious laughter and the gusto he brought to every conversation.