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Posts Tagged ‘communications’

ASCII

Characters in a computer system are stored using numeric codes. Characters in a computer system involve any alphanumeric character, punctuation characters, symbols like dollar or pound sign, and special non-printing control characters like ENTER.

The ASCII (American Standard Code for Information Interchange) code was created on the early 60’s to represent all characters in the English alphabet and it is referred to as a character set. Initially created using 7-bit codes, ASCII represented up to 128 characters, starting from code 0 up to code 127. ASCII was later extended to use 8-bit codes, and was capable of representing up to 256 characters, from code 0 up to code 255. The extended characters included letters which are not part of the English alphabet like ñ.

Clearly ASCII faced severe limitations when alphabets other than English had to be represented, like Chinese, Japanese, Arabic, Russian, and others where the alphabet has many more characters and are very different from those in the English alphabet.

Unicode

A number of standards and character sets have been created to handle the limitations imposed by single octet coded sets like ASCII. The Unicode standard, introduced in the early 90’s by the Unicode Consortium, is a fairly recent character set designed to support not only the languages mentioned above but many other languages of the world. The Unicode standard, developed in parallel with the International Standard ISO/IEC10646 (also known as the Universal Character Set), identifies each character in the set by an unambiguous name and a positive integer number called its code point. Instead of mapping characters into single octets, Unicode separately defines what characters are available, how it maps each to a unique code point, and how it encodes those numbers.

The Unicode standard can potentially support over 1 million characters, each mapped to a code point between 0 and 1,114,112. This allows computers and electronic communication devices to represent and store several other alphabets like Latin, Greek, Hebrew, including ancient and modern alphabets. Introduced in 2011, Unicode 6.0 is the most current version of the standard.

One of the advantages of the Unicode standard is that Unicode’s first 256 code points correspond with those of ISO 8859-1, the most popular 8-bit character encoding for Western European languages. As a result, the first 128 characters are also identical to ASCII.

So Where’s the Catch?

Software the runs on computers have to “marry” with one character set but also support other character sets. You can see that in operating systems, communications software, software tools, as well as in applications.

Software that runs on computers do so using several different languages around the world. Electronic documents like web pages or PDF documents are written in several different languages. If you want to be able to read those documents written in a language other than English or German or French, your computer system should support those other character encodings so that the content is correctly presented.

Добро пожаловать, Мария Шарапова любит теннис

The previous headline says ‘Welcome, Maria Sharapova likes tennis’ in Russian language, which uses the Cyrillic alphabet. If your computer system or web browser default character set supports the Cyrillic alphabet, you should be able to see something like:

If the default character set of your system or web browser does not include support for the Cyrillic alphabet then you will see some garbled text; check the text encoding used by your browser or your system (go to the View menu).

Typically, different computer operating systems use different default character sets, and usually have different ways of specifying the default character set to be used. When documents are created in different computer systems and are using different character sets, documents created in one system may not display text properly in the other system or may not display the text at all. For instance, if you want to read the Adobe Reader (PDF) version of the manual of your Japanese branded digital camera, your system needs to include support for the Japanese characters so that text will display correctly.

When computer systems are using different character sets but these character sets are compatible then only some characters may not display correctly; this usually happens when the character exists in one character set but not in the other, or when the character exits in both sets but, their numeric code is different or the character is represented by a different number of octets. This could be the case when visiting a website created in the German language where, only some characters are not found in the English alphabet.

Fortunately, many computer programs and software automatically translate characters behind the scenes when different character encodings are used between computer systems; we don’t even notice that’s occurring and we can happily read those documents.

You must be kidding! How did you type those letters!? We don’t have keyboards with the Russian alphabet (here in the U.S.) I don’t know that but, I only went to Settings, General, Keyboard, International Keyboards, in my iPad (get one if don’t have one) and added the Russian keyboard. Here it is.

Questo, que lotro, sănătate!

References

ASCII http://en.wikipedia.org/wiki/ASCII
Character Encoding http://en.wikipedia.org/wiki/Character_encoding
Unicode Consortium http://www.unicode.org/
Universal Character Set http://en.wikipedia.org/wiki/Universal_Character_Set
Another early character encoding http://en.wikipedia.org/wiki/EBCDIC

20110818-015908.jpg

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It seems my earlier “clarifications” fell really short and did not give a complete picture regarding the wireless network issues. Here is more…

1) With my earlier post I was not trying to shiFt the blame away from AT&T for the network issues or dropped calls. My intention was/is laying out the elements involved (technical mostly) in wireless comms so that we may be able to suggest solutions or have a more informed opinion. But if someone still insists in criticizing, do criticize the right place having a better and clearer picture of what’s going on.

2) My earlier “the wireless network is a huge huge collection of hardware” fell very short of how complex the wireless network can be because it is not only about size (and huge size should not justify crappiness) it also includes quality, and usually more than one wireless carrier is involved; see the comment Gregg Thurmanover posted on macdailynews.com regarding the New York Times article “AT&T Takes the Blame, Even for the iPhone’s Faults”:

“The big problem with user experience is that they haven’t a clue why they are having a problem. They use ATT but the person they are talking to uses Verizon (or something else). Is the dropped call ATT’s fault, or is the fault at the other end? Without proper recording and analysis technologies, with complete disclosure by all the carriers, NOBODY knows where the problems exist.”

The reality is AT&T cell phone users connect/call not only AT&T cell phone users but also Verizon, or T-Mobile, or Sprint cell phone users. This makes “blame AT&T” the more difficult to assert (looks like diversifying the blame would be more accurate; an instance would be the iPhone 3G radio issue suggested in the NYT article, which is part of the hardware networking devices I talked about in my earlier post).

Reality means, every cell phone call (signal) travels through a [usually] big number of different and diverse wireless networks (and at times wired as well if your call goes to/comes from land line) before it reaches the other end (and this is sometimes true even if calling an in-network user).

It also means.., let’s say we are in New York cell phone calling a friend in San Francisco, whose carrier is different than ours, in a nice day for the continental US and the call is dropped (frustrating it is). Who, what do we blame? Man, it is very difficult to know what happened in between and why. I wouldn’t know and couldn’t explain. But we very easily throw the blame to our carrier because it is the “visible” suspect, who else could we blame? Understandable but honestly, we have no clue of what happened much less who is to blame.

Technical note: In this scenario of so far away calling, your call likely travelled wirelessly within your city/region portion. After that, we don’t know how it went to SF, although most likely fiber optic (or other wired medium), or it could have gone mixed travel, wireless and wired. I, as a user, don’t know how my call was carried, and I don’t care, I just want NO fumble. And the same “could have gone mixed travel” pattern very much applies for a wireless call within the same city same carrier.

3) Some say images help to understand things. Has anyone seen how the wireless networkS (yes in plural) look like from atop? Not me. Not like a spider web; spider web seems too structured for a wireless network; probably on some cities/places only. Like a fish men net (similar to our interstate highway system)? Maybe on some places of the country. Concentric circles? Not likely but who knows. The image I tend to lean most is the one of a collage of [mostly unstructured] networks sewn together.

4) We have to accept the diversity of our landscape. The wireless network solution for a [New York] city is not and will not be the same for places like The Grand Canyon. Means the wireless network is as diverse as our landscape; building a network in some places will be nearly impossible, some places do not financially justify building it at all, and in some places is not even necessary to build one. These factors perhaps play part in an assessment for a carrier to determine whether to build or not to build a wireless network. This is for those talking/complaining about “poor coverage”.

5) What do we want out of the wireless network? If we see the network pipes as threads this is what we want:

  • Larger/longer threads – greater coverage.
  • Better threads – reliability (lesser drops, lesser noise).
  • Thicker threads – capacity (bandwidth), more “water” in less time.

So what with all these clarifications? If you want to blame your carrier less frequently…

  • Try to stick with that carrier that has the fewer networks sewn (if you can determine that).
  • Try to stick with that carrier having/building/upgrading better technology for the wireless network. A simple example from the wired world… For my land line phone service I would subscribe with the company using fiber optic for the wires over the one that still using copper; the company using fiber optic will likely have less trouble carrying my call and it will connect me faster. I don’t know much about the different wireless technologies but the criteria holds, go with the one having better technology for carrying wireless signals (the larger network with “same-kind” technology – coverage, the more resistant to obstacles – strength, greater capacity – faster). An instance would be  choosing 3G over EDGE.
  • Try to go for the carrier with LARGER/GREATER self-owned wireless network (if you can determine that).
  • If you travel abroad frequently it won’t matter what home carrier you pick, your call will usually be carried by multiple carriers in different countries to the other end. In this case you may want to go with the lesser cost for the wireless service.
  • If there is only one carrier in your area and cannot live without cell phone and cannot move then you are in a pickle and yes, you can keep blaming your carrier.

In summary…, because of the complexity of the wireless network and the inherent weaknesses of wireless signals it makes really hard to know what failed (specially when it’s the signal getting lost) and who is to blame. Nevertheless, carriers have to do their best to keep a good signal up and running; the wireless carrier that can achieve that will get the most wireless subscribers.

Even though I’m not a cell phone user, I like phone communications (wired or wireless) and even more when they work. It felt really cool when I had the chance to experience Nextel’s then just introduced walkie-talkie technology; I was able to connect/talk with a coworker in Monterrey while I was in Mexico City, instantaneously after the push of a button!!! (no dialing) If you know about the topographical shape that separates those two cities (you can check Google maps) and you know no satellite was involved, then you tend to believe telecommunication is magic.

What phone carriers do for us is already amazing.

Questo, que lotro.., salud!

walkietalkie

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