Feature Article – Understanding the 802.11n high-bandwidth wireless network

Introduction

Now that the 802.11n high-bandwidth wireless-network standard has been declared a final standard, the price of 802.11n-compatible wireless-network hardware will come down to more affordable levels. This will lead to you considering upgrading your wireless network to 802.11n whenever the time is right to renew your home-network IT hardware.

The 802.11n access point

This works in a different manner to the 802.11a/b/g access points we are so used to. Basically, these units use a “multiple in, multiple out” methodology with “front-end diversity”. They will typically have two or three aerials with each aerial serving a particular transceiver. Some units may have an aerial serving a receiver as well as the two aerials serving two transceivers. It is totally different from “antenna diversity” which is used on most 802.11b/g routers and access points, where one transceiver works with two aerials, choosing whichever has the best signal strength.

These access points and the network client devices that connect to them also make use of “constructive multipath” to improve their quality of reception.This is different from the “destructive multipath” often experienced with FM radio and analogue television. Here, signals picked up as reflected signals are mixed with signals received by line-of-sight and “worked out” as a data stream.

The premium-priced 802.11n access points will be typically dual-band in which they can work on the existing 2.4GHz band or the newer 5GHz band. Some of this equipment may be able to work on both bands, as though there are two access points in one box.

Access Point Types

Single Band

These access points use a single access point that is set up to work on one band, typically 2.4GHz, but some of them work on 5GHz as an “add-on” access point.

Dual Band, Single Radio

These access points are like a single-band access point but can be set by the user to work on either 2.4GHz or 5GHz, but not both of the bands.

Dual Band, Dual Radio

These access points, sometimes described as “simultaneous dual-band”, are effectively two 802.11n access points in one box with one working on 2.4GHz and the other working on 5GHz.

Access Point Operating Modes

Primary Operating Modes

A typical 802.11n access point can be configured to work in one of two primary operating modes – a “compatibility” mode or an “N-only” mode.

Compatibility Mode

This mode, known as Mixed Mode or G-compatible mode allows 802.11g wireless network hardware to work from the same access point alongside 802.11n equipment. The limitation with this mode is that the wireless network works to a “worst-case” scenario with throughput that doesn’t hit the standards for an 802.11n segment. You will still have the larger coverage and service reliability with the 802.11n equipment and this benefit may pass through to 802.11g equipment

N-only Mode

This mode allows the access point to work only with 802.11n equipment and gives the equipment full wireless throughput as well as the full reliability of the standard.

Wideband vs Standard Channels

802.11n access points can run their channels as either “standard” 20MHz channels or 40MHz wideband channels which can yield higher throughput. The wideband channels also make use of a “standard” channel as a “base” channel for the double-width channel.

The preferred method of operation is that a 2.4GHz access point works on “standard” channels and most such access points will be set to have this kind of behaviour by default. But you can run these access points on the wideband channels with the limitation of poorer compatibility with 802.11g devices. If you are running a 2,4GHz access point in a manner to be compatible with regular 802.11g devices, it would be a good idea to stick to “standard” channels. If you are running 5GHz access points, you can get away with using the wideband channels and I would prefer setting up a 5GHz 802.11n extended-service-set to work this way.

The number of streams a device can handle

An 802.11n wireless device will typically be rated as being a single-stream, dual-stream or multiple-stream device. This relates to how many streams of data the wireless device can handle. All Wireless-N (802.11n) access points and routers will typically be either a dual-stream type or a multiple-stream type in the case of premium devices. Similarly, laptops with integrated Wireless-N capability; and add-on Wireless-N products will typically be dual-stream devices.

The main class of devices that will handle only one stream will be primarily-battery-powered devices like smartphones, WiFi VoIP phones, and WiFi-enabled digital cameras / portable media players because the single-stream ability won’t be intensive on these devices’ internal battery resources. Similarly, the idea of a single-stream Wireless-N network interface will also appeal to applications where size or cost do matter.

Other points to know

Best practice with dual-band equipment

If you are running dual-band equipment, especially dual-band dual-radio equipment, it would be a good idea to use the 5GHz band as N-only mode, while 2.4GHz works as compatibility mode. If you are running dual-band single-radio equipment, you will need to use older 2.4GHz equipment to run an 802.11g service set with the dual-band single-radio equipment on 5GHz N-only mode.

Use of aftermarket antennas

You can use external aftermarket antennas (aerials) with 802.11n equipment as long as all of the antennas are of the same type. This may work well if you replace the omnidirectional whip aerials with stronger omnidirectional ones. Then you may have to space the aerials further apart for the front-end diversity to work properly The main difficulty you will have is using directional aerials, in which case you may need to look for directional aerials optimised for 802.11n setups.

As well, if you are running dual-band dual-radio equipment, you will have to use antennas that can work on the 2.4GHz and 5GHz bands rather than antennas optimised for the 2.4GHz bands.

Shaping your 802.11n wireless network – the ideal upgrade path for your wireless network

I will be talking of WiFi networks that work on a particular technology and with a unique SSID and security parameter set as an “extended-service-set”. This allows me to cover setups where there are multiple access points working with a particular configuration.

You may be tempted to construct a multiple-access-point extended-service-set with an 802.11g access point and an 802.11n access point working in “compatibility mode” connected by an Ethernet or HomePlug wired backbone. The simple answer is "don’t”. You will end up with your wireless network having reliability problems especially as devices roam between the different access points and switch operating modes.

The simple answer would be to run different extended-service-sets with at least one access point for each WiFi technology. They are set up with different ESSIDs (such as SSID for the G cloud and SSID-N for the N cloud) with the wireless stations choosing between the different ESSIDs. The only thing they can have that is common is the WPA security parameters, and a common wired backbone which can be Gigabit Ethernet or HomePlug AV.

This could be achieved through deploying an existing 802.11g router that is set up as an access point and working on “SSID-G” and one channel while a newer 802.11n router working as the Internet “edge” is set to “N-only: or “compatibility” mode in the case of a single-band 2.4GHz unit, and set to “SSID-N” and a different channel.

As you evolve your wireless network, you may want to work towards establishing a 2.4GHz 802.11n “compatibility-mode” extended-service-set and a 5GHz N-only extended-service-set. You then upgrade your portable computers to work with dual-band 802.11n network interfaces or add dual-band 802.11n network adaptors to your existing equipment. The 5GHz extended-service-set will come in handy for high-throughput activity like video streaming and related applications while the 2.4GHz extended service set can work well with voice applications, smartphones, Internet radio and similar applications where throughput doesn’t matter.

If you are upgrading a wireless hotspot to 802.11n, it would be preferable to make sure your hotspot’s extended-service-set is on the 2.4GHz band and operating in “compatibility” mode so that customers can still use their existing 802.11g hardware on the wireless hotspot.

Some issues may occur with dual-band networks where the 5GHz extended-service-set may not cover the same area as the 2.4GHz extended-service-set. This is because the 5GHz band is of a higher frequency and shorter wavelength than the 2.4GHz band and is best demonstrated by AM radio stations being receivable at a longer distance compared to FM radio stations. It can be rectified by deploying a dual-band single-radio access point working on the 5GHz band in to the 5GHz extended-service-set as an infill access point.

Conclusion

Once you understand the 802.11n wireless standard and what it can and cannot do, you can make sure that you get the best out of the new standard while gaining the maximum mileage out of the existing wireless-network hardware.

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Telstra’s Mum 2.0 Videos about social networking

This series of short video lessons produced by Telstra gives a very good explanation about social networking sites like Facebook and how to use these sites sensibly. They are mainly pitched at older folk who most likely don’t understand these sites and describe a Facebook profile in a similar way to your home that you had just moved in to.

They talk of the primary concepts such as

  • adding online friends such as Facebook Friends to your profile
  • uploading pictures to your profile and what pictures you should upload
  • use of the social network site’s applications like FunWall, FarmTown, the many Facebook Gifts application and online “love meters”
  • joining online groups and “fan pages” within the social network and
  • tuning your privacy settings for your needs

If you are viewing the videos from this blog post, there will be a series of video thumbnails at the bottom of the video screen when the videos finish.

This will augment some of the posts that I have put up in my blog about getting the most out of Facebook and other social networks.

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Now the bathroom scales can connect to the home network

 Withings – Home Page

Why Fit | Wi-Fi Networking News

WiFi-enabled bathroom scale slides into USA, overweight Yanks sluggishly back away | Engadget

My comments on this next step for the home network

When I was young, the typical kind of bathroom scales that were commonly available were of a mechanical type that needed adjustment before anyone could be weighed. As well, a person who didn’t have good eyesight couldn’t easily weigh themselves and had to require someone else to read the weight. There was a trickle of electronic scales but these were very expensive and mainly available through selected mail-order catalog stores rather than the homewares departments of a typical department store.

In the last 20 years, we have seen the arrival of cost-effective electronic bathroom scales that had a large digital display or, in some applications, voice synthesis; didn’t need to be adjusted every time each person weighed in and could allow a person with limited eyesight to weigh themselves. These units are becoming available through most homewares stores and departments.

This bathroom scales is the first unit that does more than the typical bathroom scales can do. It can measure fat mass and body mass index; but works with a Web portal that keeps record of this data for up to 8 members of a household. The data is transmitted to the portal using the WPA-secured Wi-Fi segment of your home network and is kept in a secure manner on the portal. As well, there is a local application available for the Apple iPhone / iPod Touch platform which provides the data in a manner optimised to that handheld device. But the Web dashboard can be visited through a regular Web browser setup.

From what I have seen of this device, there isn’t anything about what is involved in integrating the scales in to a secure wireless network. As far as I am concerned, these are the kind of devices that WPS-Push-Button-Connect is made for. Another thing I would like to see for these scales is an API being available so that one can write software such as integration into various desktop, network and Internet health-records programs.

As well, this has actually been the first kind of personal-health device available on the market that is able to be part of a home network. It could pave the way for more of these networked health-measurement devices to be made available for home-network use.

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Facebook | Fighting the Battle Against Money Scams

Facebook | Fighting the Battle Against Money Scams

My comments and further explanation on this topic

This article in Facebook’s blog touches on a very common risk that can affect any social-networking site and user community. It mainly talks of the “money scam” which is really similar to the common “Nigerian” or “419” scam that many of us have encountered through the spam that comes in our mailboxes.

In the social-network version, a fraudster “sets up shop” on a Facebook or similar site and takes over a user’s account. They will then message the user’s social-network friends claiming that they are in another land and out of money. This will be via a message on the Wall or a direct message via the Inbox or a Chat session. They will typically require the friends to wire a huge amount of money to the scammer.

If you do receive one of these kinds of contacts from your friends via a social-networking Website, make a call by regular telephone to the number that you know the friend (or a person that you are sure knows them well such as their spouse / partner, child or employer) can answer such as their home or mobile number. Here, I would prefer to make a voice call rather than use text messaging. Then you can ascertain whether it is the friend who is in need or simply a scam taking place. As well, confirm the situation with mutual contacts. If the friend’s account is being compromised, tell them to change the account’s password immediately. Sometimes, companies like Facebook can lock down a compromised account and e-mail the account holder about what is going on. Then they advise the account holder to change their password immediately.

As well, know what resources do exist in your social-networking service for reporting compromised user accounts and be ready to identify “out-of-character” messages, links or pictures posted up on these services by your friends. For Facebook users, the link is http://www.facebook.com/help.php?page=420 .

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Social-networking sites help families in touch

 Networking sites help families in touch | The Age (Melbourne, Australia)

My comments on this topic

This article describes how the social-networking site is existing in the context of keeping the family in touch. A common but obvious application may be a teenager who is travelling overseas during “gap year” or a child who is on an exchange-student placement or similar program wanting to keep “home” up to date with whatever is going on during their travels.

Similarly, some users use these services as another tool to keep in touch with long-distance relatives and friends. This can help in reducing the number of long-distance phone calls needed to keep in regular touch.

The article talked of the possibility of parents doing something embarrassing on the teenager’s Facebook or MySpace page such as putting up embarrassing photos best reserved for the 21st or making embarrassing comments about the child’s status updates or photos, which could lead to parents and teenagers not establishing the electronic friendships that are part of the social networking service. It talked of adopting a “look but don’t touch” attitude to these pages and only commenting if you have something witty to say for example. If you do need to contact them directly, use the social-networking service’s direct-messaging function or, if they are online, use the text chat function. These techniques can also be used to set up a VoIP chat session using Skype, Windows Live Messenger or Yahoo Messenger.

Other key factors that I have observed is the technological confidence barrier that exists between the young and the old, especially those didn’t experience computer technology in their younger lifetime. This is often exacerbated through fears of privacy abuse, the shock of others knowing your wider circle of friends and relatives amongst other things when using a social-network site.

Similarly, some of these social networks are now partnering with most application and content-delivery platforms to provide a direct interface to electronic picture frames, smartphones / PDAs, set-top boxes and similar devices. This may be in the form of a “widget” or server-updated slide; direct-link to a suitably-sized Web front; or a client-side application; and can allow a summary view of what is going on with Facebook from these devices. Some of the applications may allow a quick update or photo upload from the device’s user interface. These can be useful for monitoring what is going on with your family at all times without needing to visit the desktop or laptop computer regularly.

Once you can understand what the social network site is all about, you can then use it as another tool for keeping your family circle together.

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In-vehicle networks

Peugeot intègre le Wi-Fi dans ses véhicules | DegroupNews (French language)

Chrysler confirms in-car Wi-Fi coming next year | Engadget

BMW’s ConnectedDrive brings the whole internet to your car… on EDGE | Engadget

There is a new trend concerning the small network in that the car will have its own IP-based network with a link to the Internet. This has been brought about by manufacturers making WiFi “edge” routers with a 3G wireless link on the Internet side for installation in vehicles. Similarly vehicle builders like BMW, Chrysler and Peugeot are using this feature as a product differentiator in some of their vehicle models.

But what use are these devices?

Primarily these devices provide Internet access to passengers in minivans, limos and the like; and some bus fleets are taking this further for provision of Internet access to their premium routes. Some people may also think that these routers may have the same appeal as the “component-look” car stereo systems of the late ‘70s and early ‘80s; where they only appealed to young men who were customising cars and vans in order to impress others.

What could they offer

Like the typical home Internet-edge router, all of these routers offer Ethernet and WiFi for the local network connection, which means that car devices can be directly connected to these Internet gateways. This can lead to online applications being made available to integrated or aftermarket-installed equipment which is being considered as sophisticated as a typical personal computer.

Ethernet port on the car stereo

A car stereo system could have an Ethernet port and support the same kind of network media services as some of the in-home entertainment systems offer. One application could be Internet radio functionality, where the set could have access to the Frontier Platform, Reciva or vTuner Internet-radio directories; and be able to pull in Internet radio from around the globe. An idea that may come to mind is the concept of young men “cruising” along Chapel Street in South Yarra; Campbell Parade in Bondi; Surfers Paradise or other “show-off” streets in Australia or coastal USA with the dance grooves from Heart London’s “Club Classics” program thumping out of the “subs and splits” in their souped-up machines during a special UK long weekend. Another function would be to support the “visual radio” platform that is part of most mobile-phone FM-radio implementations.

Another more interesting application is an in-car DLNA media network. The 3G WiFi router could work as a WiFi client when, in the presence of the home network, cause syncing of content between the home DLNA media network’s server and a hard disk built in to the car stereo. This allows for newly-added music content from the home network and up-to-date podcasts to be available in the car.

Similarly, there could be the ability to play content held on a DLNA-capable WiFi-enabled mobile phone or portable media player through the car speakers. As well, a small NAS like the Thecus N0204 miniNAS which I have mentioned about in this blog could be shoehorned to work from a car’s power supply and become a DLNA-enabled media storage unit for the car.

This functionality can be extended to the back seat in the form of access to newer video content from the home network or access to online video content to the back screens. As well, the vehicle’s music system could work as a DLNA media server for use in providing media at secondary locations like holiday homes or worksites. This would be in conjunction with a DLNA-compliant media player connected by a WiFi segment between the vehicle and the building’s network.

There is more information about how DLNA is investigating implementation of this standard in the automotive context in this white paper (PDF) at their website.

Ethernet connection for navigation systems

The “sat-nav” systems can benefit from Ethernet connectivity for integrated units or WiFi connectivity for portable navigation devices. This could allow for these systems to have up-to-date information about new points of interest as well as another link for receiving real-time traffic information.

The IP feed can work very strongly with real-time information being received from the wireless Internet in order to provide updated traffic information and / or real-time service information for garages, restaurants, motels and the like. This will then allow drivers to make better decisions about their journeys such as alternate runs or use of services. It could cater for “social recommendation” functionality for the roadside services so one can go to where the food’s known to be good for example.

Support for IP-driven vehicle telemetry

The vehicle could have an Internet-based direct link to the garage that the owner has a working relationship with, or to the fleet-management service in the case of a vehicle that is part of an organisation-owned fleet. This link can allow access to historical diagnostic information about the vehicle thus allowing for informed decisions concerning what repair work needs to be taken or whether the vehicle should be pensioned off.

Similarly, there could be the ability to implement vehicle / driver surveillance techniques which can be of benefit to parents of teenage drivers or organisations who need to keep in step with workplace safety or professional-driver regulations.

In some cases like public and community transportation, it may be desireable to have IP-based closed-circuit TV surveillance that streams the vision “back to base” instead of or as well as recording it to a local hard disk. This will also please the police force where officers are in a “first-response” situation and need “many eyes and many brains working together” on an emergency situation.

Electric vehicles (including hybrid-electric vehicles)

These vehicles will typically benefit from network and Internet connectivity in order to permit flexible power management situations like optimised battery charging or vehicle-to-grid setups. They will also benefit from the above-mentioned IP-driven vehicle telemetry so that the user or preferred mechanic knows if the battery is not holding its charge in the same way that it used to, thus knowing when to have it replaced.

What needs to be done

I would prefer the in-vehicle network to be capable of working as its own network with a 3G or similar-technology WWAN as proposed by the vehicle builders in their implementation or as a member of user-selected WiFi LANs in a client / access-point (WDS) role. This can be determined by a list of “preferred” SSID / WPA(2)-PSK combinations held local to the vehicle.

The “Ethernet behind the dash” concept of using Category 5 Ethernet to create a wired LAN amongst in-vehicle subsystems has to be researched, This includes how Category 5 Ethernet can handle the problems associated with an automotive electrical system which is known to be very noisy or prone to surges and spikes such as while the vehicle’s engine is being started.

Once the concept of the automotive local area network is researched properly, there is the ability to use it as a simple data conduit across vehicle systems for all data-transfer applications, not just for Internet surfing by passengers.

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BBC NEWS | UK | Magazine | 10 things you didn’t know about Ceefax

 BBC NEWS | UK | Magazine | 10 things you didn’t know about Ceefax

My comments on Ceefax, Austext (and teletext services) in relationship to the connected home

People, like myself, who watched what was happening with consumer technology through the 1970s and 1980s may have heard of “teletext”. This technology, which was launched by the BBC in 1974 and Channel 7 Australia in 1980, was a text-based information service that was delivered alongside the television picture in the vertical blanking part of the picture.

Typically, it required a suitably-equipped television set or regular television set used alongside a tuner-decoder box and users were able to bring up pages of information through the device’s remote control which had a numeric keypad. Infact, there have been some devices that connected to or were integrated in a computer that allowed the computer to pull off the information from a teletext service.

The common operating practice was, when you pressed the “Text” button, you saw a menu with a list of pages to go to. These typically had a number after them which you keyed in to the remote control when you want to view them. There was also an “up-down” button so you can “flip” through the pages. In a typical setup, you had a page like 101 or 120 as a “news index” with the stories listed like in the Web or on an RSS feed. Then you could key in the page number to view that story.

The system was primarily intended as a tool for providing user-optional text subtitles for hearing-impaired viewers (and people watching TV in noisy environments). But it has become a “preproduction”  showcase of what the Web concept was about. Most often, sports fanatics, especially horse-racing fanatics, used these services to find out what was happening with the sporting fixtures (and which runners to place bets on). In Australia, the Austext service was on televisions installed in TAB betting shops and sports bars. As well, a concept “connected home” in the early 1980s such as one that was established in Milton Keynes had to have a teletext-equipped TV set as part of the equipment that was provided.

One time, I had worked with some friends in helping them follow the New South Wales state election the Austext way. This was through me noting down page numbers for aggregate data and “desired electorates” where their relatives lived. When the TV showed up the pages, it had the latest counts up on the screen for the parties concerned. This was certainly a taste of things to come with following elections on the Web, where you could gain the latest results on Web pages established by media outlets or the state’s electoral offices, sometimes with graphs or coloured maps that reflect these results.

There had been improvements, mainly in the form of “fastext” where you navigate pages using the coloured buttons on the remote control or “TOPtext” where you navigate pages with a DVD menu page experience. But these worked if the TV set was tied in properly with the method of operation.

Some parts of the Web, like the use of RSS feeds and indexes, mimics the classic index pages; and even the news pages and the blogosphere provide the same kind of “fresh updates” that teletext had offered.

This certainly shows that some of the older technologies have laid the foundation for the connected lifestyle.

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RAW Image Support – W7/Media Center 32/64 bit « digitalmediaphile

RAW Image Support – W7/Media Center 32/64 bit « digitalmediaphile

http://www.fastpictureviewer.com/codecs/ 

My comments on these codecs

Barb Bowman (http://digitalmediaphile.wordpress.com) has found a useful resource on this website http://www.fastpictureviewer.com/codecs/ for those of you who want to keep the Windows platform relevant to your high-end digital photography needs.

Here, this site provides downloadable codecs and plugins that work properly with the RAW image files that are part of high-end digital photography. Some of these codecs may work directly with Photoshop for Windows or simply become Explorer codecs for use in thumbnails and Windows Live Photo Gallery.

The main thing I have liked about this is that the codecs don’t cost anything and, from Barb Bowman’s experience, aren’t likely to bog your computer down. This may avoid the need to just use the Apple Mac for your digital-imaging needs.

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Atheros Buys Intellon to Give Wi-Fi a Powerline Backbone – This could be a marriage of convenience for the home network

Atheros Buys Intellon to Give Wi-Fi a Powerline Backbone | GigaOm.com

My comments on this merger

Atheros, who have strong prowess in the WiFi market, have bought Intellon who make a majority of the HomePlug chipsets and reference designs. This merger is one which I see as a marriage of convenience because of HomePlug, whether the 1.0 Turbo or AV variety, exists as a complementary wired network medium to WiFi especially as the home or small-business network is concerned.

I have often blogged about, given advice on and set up home networks consisting of a wireless router and another wireless access point that are interlinked with a HomePlug backbone. Both of these access points (the wireless router’s access point and the extension access point) are on the same WiFi technology and work together to provide an “extended service set” of multiple access points to extend coverage. This marriage of convenience could provide for more of the WiFi access points with integrated HomePlug connectivity; of the ilk of the Solwise PL-85PEW and the Netcomm NP290W. It can also permit more manufacturers to develop routers that support WiFi wireless, HomePlug powerline and Ethernet LANs.

The only problem with many small networks is that the only “no-new-wires” technology that is for use in these networks is WiFi wireless, typically provided by a wireless router’s integrated access point. HomePlug powerline networks are usually forgotten about by most people who are involved with designing, manufacturing or selling small-network hardware.

If this merger encourages wireless-hardware manufacturers to consider supplying HomePlug in their small-network hardware portfolios, it may then improve the take-up of this technology as an alternative to WiFi or simply to complement and improve WiFi networks.

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Is this the new direction for Internet radios?

 Pure Sensia DAB / WiFi radio gains touchscreen, streaming and Facebook

Pure Sensia radio microsite

My comments on this Internet radio

The Pure Sensia DAB / WiFi radio is now demonstrating that the concept of a mobile Internet device is approaching the Internet radio domain. This unit, which is the size of a low-end boom-box and equipped with stereo speakers, will have the usual Internet radio functionality like online access through a portal as well as DAB / FM tuner and access to music held on a DLNA-compatible home media network. But it has the kind of functionality associated with the mobile Internet devices by having access to weather, RSS webfeeds and the ubiquitous Facebook social network. There is even room to expand the functionality through downloaded applications just like you can with most smartphones.

Another thing that impressed me about this Internet radio was the use of an RF link rather than an infrared link for the set’s remote control. One major advantage is that you don’t have to point the remote control at the set to control it. But the main method of operating this radio is through the touchscreen just like you can with the Apple iPhone or iPod Touch; or a well-designed information kiosk. Even the task of adjusting the volume or tuning the FM stations is through a natural interface of you sliding a volume control or FM tuning pointer.

If a manufacturer like Pure can develop an Internet radio that works like an MID, who knows what will happen in the class of connected consumer-electronics devices? Will we end up with more of the converged devices that become more like mobile Internet devices?

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