30 Years of the Digest ... founded August 21, 1981
The Telecom Digest for March 24, 2012
====== 30 years of TELECOM Digest -- Founded August 21, 1981 ======
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Date: Fri, 23 Mar 2012 01:00:13 -0400 From: Monty Solomon <firstname.lastname@example.org> To: email@example.com. Subject: 'Turn Off All Electronic Devices:' And What Happens if You Don't Message-ID: <firstname.lastname@example.org> 'Turn Off All Electronic Devices:' And What Happens if You Don't By Scott McCartney March 7, 2012 It happens on just about every flight now, say flight attendants. The plane's door closes and it's time to turn off personal electronic devices. And there's always at least one person who keeps talking, texting, tweeting, playing, watching or emailing-and ignoring stern orders to power down. On rare occasions, a confrontation erupts, such as actor Alec Baldwin's widely reported removal from an American Airlines plane in December. Although airlines say they don't keep track or won't disclose how many passengers get bounced off planes for refusing to switch off devices, flight attendants say it's now the No. 1 spark for unruly behavior. ... http://online.wsj.com/article/SB10001424052970204781804577267304080904804.html (The Wall Street Journal site requires subscription in order to read full articles - mod)
Date: Thu, 22 Mar 2012 23:57:23 -0400 From: Monty Solomon <email@example.com> To: firstname.lastname@example.org. Subject: Hot Spots That Don't Stay Home Message-ID: <email@example.com> Hot Spots That Don't Stay Home By DAVID POGUE March 21, 2012 Ah, the Internet! The source of so much goodness. The font of e-mail, news, chat, TV, blogs, books and Facebook. What would we do without it? If you're like most people, you know perfectly well. Once you're out of the house and on the road, you're out of Wi-Fi range. You're either offline completely, or you peek at the Internet through the tiny screen of a smartphone. There is another way. You could get a broadband cellular hot spot, like the MiFi, a tiny, self-powered base station that creates a Wi-Fi bubble from your pocket or purse. Nearby laptops, iPads and iPod Touches can get online, wherever you happen to be. These cellular hot spots are fantastic companions on long car rides, offsite meetings, movie shoots on location, trade show booths, hotel rooms, beaches, airplanes stuck on runways and anywhere else where Wi-Fi is costly or nonexistent. Unfortunately, the hot spots from Verizon or AT&T cost at least $50 a month. As of this week, there's a new option from NetZero. It may not change the game, but it does change some of the rules. ... http://www.nytimes.com/2012/03/22/technology/personaltech/netzero-clearwire-and-other-ways-to-get-a-hot-spot-to-go-state-of-the-art.html
Date: Fri, 23 Mar 2012 01:00:13 -0400 From: Monty Solomon <firstname.lastname@example.org> To: email@example.com. Subject: To Tweet From 30,000 Feet: Picking Planes Wired for Wi-Fi Message-ID: <firstname.lastname@example.org> To Tweet From 30,000 Feet: Picking Planes Wired for Wi-Fi By Scott McCartney March 21, 2012 More passengers are downloading books, sending Tweets and updating their Facebook pages in the middle of a flight-even as they complain about steep prices. Currently, about 1,700 planes in the U.S. have Internet access, including the entire fleets of Virgin America and AirTran, Delta Air Lines' entire domestic fleet, and a sizable number of planes flown by American and Southwest Airlines. Airlines say Wi-Fi usage-the percentage of passengers paying for Internet access-is picking up, driven partly by the popularity of tablet computers and partly because more planes have the service. Currently about 8% of passengers use the service, up from 4% at the end of 2010, according to In-Stat, a research and consulting firm. That likely will reach 10% of passengers by the end of this year, In-Stat says. Virgin America, which has both wireless hot spots and standard power plugs on all its 50 planes, says some cross-country "nerd bird" flights between tech strongholds like San Francisco and Boston have averaged 26% of passengers paying for airborne Wi-Fi service, even on redeye flights. Overall, the airline is hitting about a 16% usage rate. Airlines say popular activities include book downloads, Facebook updates and real-time flight-tracking. ... http://online.wsj.com/article/SB10001424052702303812904577295622065558432.html (The Wall Street Journal site requires registration - mod)
Date: Fri, 23 Mar 2012 10:21:03 -0400 From: "news" <email@example.com> To: firstname.lastname@example.org. Subject: Re: What Hath Bell Labs Wrought? The Future Message-ID: <email@example.com> On Thu, 22 Mar 2012 19:38:58 -0400, Jim Bennett <firstname.lastname@example.org> wrote: >On 2012-03-21 11:02, Eric Tappert wrote: >> >> The problem with these frequencies is that they do not toggle all the >> bits in the encoding, thus testing at those frequencies is incomplete. >> Accordingly, the test sets for digital circuits test at 1015 Hz, >> wihich causes all the bits to toggle in the encoding. >> >> There is nothing "magic" about 1 kHz. It does sort of correspond to >> the peak energy in voice (even though every voice is a bit different). >> Note that any sampling rate would have the same problem with >> frequencies that are, as Bill put it, "even sub-multiples" of the >> sampling frequency. >> >> I doubt that most engineers would consider this a big screw up by Bell >> Labs, and certainly there are lots of other cases where the impact was >> greater. All in all, they did a pretty good job of designing the >> telephone network... >> >> ET > >Every "milliwatt" test tone I have seen is set at 1004 hertz. I am not >saying there is no such thing as a 1015 hertz source, just that this is >the first I am hearing of it. Maybe I just need to get out more. > >Over the years I have heard at least three different explanations for >why the 1000 hertz test tone was changed to 1004 hertz. It is >certainly true that sampling a 1000 hertz tone at 8000 samples per >second will result in the exact same eight patterns, repeating ad >nauseum. [assuming that the test tone is stable]. This is one of the >explanations I have heard, i.e., that it is not a rigorous enough test >for the A/D converters and/or the actual line drivers. I have always >found this somewhat dubious, as my experience with these things is >that they either work or they don't. Timing slips and jitter were the >primary problems in the days of true DS-1 signaling over copper, and >testing often involved sending "all ones." > >Another explanation I have heard is that 1000 hertz was never a problem >until ESF came along. Extended Super Frame finds the framing bit by >looking for the one bit out of 193 that consistently alternates between >a "one" and a "zero" with each frame. Apparently the 1000 hertz tone >would result in actual time slot bits doing the same thing, and bumping >it up to 1004 solved the problem. I am not saying this is fact, just >relating what I have heard over the years. > >Jim >================================================== >Speaking from a secure undisclosed location. I didn't look it up but I do recall that 1015 Hz was used, as was 1004 Hz (thanks for reminding me...). Perhaps the 1015 Hz was the European version. In any event, any small offset would do as all the bits in the encoding would change over a reasonable time frame. As for the framing issue, to generate an error would require that a line error caused a loss of framing while the channel tone test was active, then the re-framing algorithm locked on to the channel signal instead of the "real" framing bit. This would cause, when the tone disappeared, another loss of framing error and recovery. That scenario is highly unlikely. However, if it occured the voice channels would be messed up until the tone disappeared. As for ESF, it used a unique pattern of ones and zeros in the framing bit position to establish froming and determine which frame held the signaling bits. It is even more unlikely that a constant pattern in a time slot would mimic this pattern. In any event, normal tolerances on test sets and link timing would likely mean that problems anticipated would rarely occur. I suspect the test frequency change was made according to the Bell Labs "belt and suspender" policy... ET
Date: Fri, 23 Mar 2012 19:54:17 -0400 From: email@example.com (Jim Bennett) To: firstname.lastname@example.org. Subject: Re: What Hath Bell Labs Wrought? The Future Message-ID: <4F6D0D29.email@example.com> On 2012-03-23 10:21, news [Eric T.] wrote: > I didn't look it up but I do recall that 1015 Hz was used, as was 1004 > Hz (thanks for reminding me...). Perhaps the 1015 Hz was the European > version. In any event, any small offset would do as all the bits in > the encoding would change over a reasonable time frame. > > As for the framing issue, to generate an error would require that a > line error caused a loss of framing while the channel tone test was > active, then the re-framing algorithm locked on to the channel signal > instead of the "real" framing bit. This would cause, when the tone > disappeared, another loss of framing error and recovery. That > scenario is highly unlikely. However, if it occured the voice > channels would be messed up until the tone disappeared. > > As for ESF, it used a unique pattern of ones and zeros in the framing > bit position to establish froming and determine which frame held the > signaling bits. It is even more unlikely that a constant pattern in a > time slot would mimic this pattern. > > In any event, normal tolerances on test sets and link timing would > likely mean that problems anticipated would rarely occur. I suspect > the test frequency change was made according to the Bell Labs "belt > and suspender" policy... > > ET > Yeah, I never liked the ESF explanation for the change to a 1004 hertz test tone. As you pointed out, ESF uses a unique bit pattern for the framing bits over 24 successive frames. If memory serves, it was the long-abandoned D1 framing [the predecessor to plain old Super Frame] that simply alternated the framing bit with each frame. Also, as you said, if a stable 1000 hertz tone results in the same eight patterns repeating, then the scenario seems even more unlikely. So what was the reason? The "belt and suspenders policy" seems possible, but there must have been a reason for it, even it was based on a purely theoretical problem. Bill's original statement about "sampling ambiguities" is still stuck in my tired old brain - Bill, could you elaborate on this? Jim ================================================== Speaking from a secure undisclosed location.
Date: Fri, 23 Mar 2012 12:37:11 -0500 From: firstname.lastname@example.org (PV) To: email@example.com. Subject: Re: FCC sues AT&T for Nigerian TDD scams Message-ID: <94CdnTOB9fBaKfHSnZ2dnUVZ_qWdnZ2d@supernews.com> "John R. Levine" <firstname.lastname@example.org> writes: >TDD relay has a dreadful problem with Nigerians calling and defrauding >people. The FCC required that operators register users and verify that >they're in the US. The suit claims that AT&T deliberately uses a >registration scheme that doesn't keep out crooks, and as a result 95% >(NINETY FIVE PERCENT) of their TDD calls are Nigerian fraud. This is a combination of a "no good deed goes unpunished" and a Tragedy of the Commons problem. TDD has always been offered on a no-questions asked basis, with the facilitator simply reading the TDD side, and typing in the spoken side. It's set up with the idea that even though there's an extra person in the loop, the deaf person has the same privacy as a hearing person using the phone system. Exactly how DO you "keep out crooks" here? I don't think there's a magic solution when there's so many ways of tunneling to a US phone line or internet address from anywhere in the world. * -- * PV Something like badgers, something like lizards, and something like corkscrews.
Date: Fri, 23 Mar 2012 18:27:33 -0500 From: email@example.com (Robert Bonomi) To: firstname.lastname@example.org. Subject: Re: FCC sues AT&T for Nigerian TDD scams Message-ID: <mdSdnWtl2NJ4m_DSnZ2dnUVZ_uydnZ2d@posted.nuvoxcommunications> In article <alpine.BSF.email@example.com>, John R. Levine <firstname.lastname@example.org> wrote: >AT&T provides a TDD relay service for which the government reimburses the >costs. According to the WSJ, the Justice Department is suing AT&T for >fraudulent reimbursement claims. > >TDD relay has a dreadful problem with Nigerians calling and defrauding >people. The FCC required that operators register users and verify that >they're in the US. The suit claims that AT&T deliberately uses a >registration scheme that doesn't keep out crooks, and as a result 95% >(NINETY FIVE PERCENT) of their TDD calls are Nigerian fraud. > > >http://online.wsj.com/article/SB10001424052702304636404577297454154404874.html > Here is a more complete article: http://www.businessweek.com/news/2012-03-22/at-and-t-accused-of-improperly-billing-u-dot-s-dot-program-for-deaf -or- http://tinyurl.com/7of6knb Intresting factoid -- claim is that AT&T erroneously billed $16 million to the U.S. Gov't. for non-US-origin 'relay' services calls over several years. DOJ is seeking 'treble damages'. RICO ??
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