Pat, the Editor

27 Years of the Digest ... founded August 21, 1981

Classified Ads
TD Extra News

Add this Digest to your personal   or  

 
 
Message Digest 
Volume 28 : Issue 204 : "text" Format

Messages in this Issue:
  Updates to Google Voice
  Skype apparently threatens Russian national security 
  Re: What is this device called 
  iPhone 3Gs encryption cracked in two minutes 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Walter's Telephones 
  Re: Wireless speed loss 
  Re: Wireless speed loss 
  Re: What is this device called 
  Re: Wireless speed loss 
  Re: Wireless speed loss 
  Re: Wireless speed loss 
  Re: Walter's Telephones 
  Re: Walter's Telephones 


====== 27 years of TELECOM Digest -- Founded August 21, 1981 ====== Telecom and VOIP (Voice over Internet Protocol) Digest for the Internet. All contents here are copyrighted by Patrick Townson and the individual writers/correspondents. Articles may be used in other journals or newsgroups, provided the writer's name and the Digest are included in the fair use quote. By using -any name or email address- included herein for -any- reason other than responding to an article herein, you agree to pay a hundred dollars to the recipients of the email. =========================== Addresses herein are not to be added to any mailing list, nor to be sold or given away without explicit written consent. Chain letters, viruses, porn, spam, and miscellaneous junk are definitely unwelcome. We must fight spam for the same reason we fight crime: not because we are naive enough to believe that we will ever stamp it out, but because we do not want the kind of world that results when no one stands against crime. Geoffrey Welsh =========================== See the bottom of this issue for subscription and archive details and the name of our lawyer, and other stuff of interest. ---------------------------------------------------------------------- Date: Fri, 24 Jul 2009 23:09:05 -0400 From: Monty Solomon <monty@roscom.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Updates to Google Voice Message-ID: <p062408c6c69026c51b7a@[10.0.1.3]> Pogue's Posts - The Latest in Technology From David Pogue July 16, 2009, 2:34 pm Updates to Google Voice It's no secret that I'm a huge fan of Google Voice. To refresh your memory, I quote myself: "Google Voice began life in 2005 as something called GrandCentral. It was intended to solve the headaches of having more than one phone number (home, work, cellphone and so on). GrandCentral's grand solution was to offer you a new, single, unified phone number, in an area code of your choice. Whenever somebody dialed your new uni-number, all of your phones rang at once. "No longer did people have to track you down by dialing multiple numbers; no matter where you were, your uni-number found you. As a bonus, all voicemail messages landed in a single voicemail box, on the Web. "GrandCentral also let you record a different voicemail greeting for each person in your address book. You could also specify which phones would ring when certain people called. (For the really annoying people in your life, you could even tell GrandCentral to answer with the classic, three-tone 'The number you have dialed is no longer in service' message.) "For people with complicated lives, GrandCentral was a breath of fresh air. It felt like a secret power that nobody else had." Then, after Google bought GrandCentral and unveiled an improved version a year later, I wrote: "Google Voice maintains all of the original GrandCentral features - but introduces game-changing new ones." The new features included free transcriptions of your voicemail (the text of those messages gets sent to you by e-mail and text message); free conference calling; dirt-cheap international calls (2 cents a minute to France or China, for example); and, perhaps most profoundly, Web-based sending and storing of all your text messages. That's a first in cellphone history; for most people, text messages scroll away off the phone after 20 of them or so, with no way to capture them. Anyway: today, some updates. ... http://pogue.blogs.nytimes.com/2009/07/16/updates-to-google-voice/ ------------------------------ Date: Fri, 24 Jul 2009 21:28:04 -0700 From: Thad Floryan <thad@thadlabs.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Skype apparently threatens Russian national security Message-ID: <4A6A89D4.5010008@thadlabs.com> Just found this on Slashdot: http://yro.slashdot.org/story/09/07/25/0015250/Skype-Apparently-Threatens-Russian-National-Security "Reuters reports that 'Russia's most powerful business lobby moved to clamp down on Skype and its peers this week, telling lawmakers that the Internet phone services are a threat to Russian businesses and to national security.' The lobby, closely associated with Putin's political party, cites concerns of 'a likely and uncontrolled fall in profits for the core telecom operators,' as well as a fear that law enforcement agencies have thus far been unable to listen in on Skype conversations due to its 256-bit encryption." ------------------------------ Date: Fri, 24 Jul 2009 21:29:56 -0700 From: Bruce L.Bergman <bruceNOSPAMbergman@gmail.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: What is this device called Message-ID: <kkpk65tatkn4uhs0nsj07vhce0aqeln3op@4ax.com> On Fri, 24 Jul 2009 10:58:29 -0400 (EDT), Tom Horne <hornetd@verizon.net> wrote: >There used to be a device that could be obtained from AT&T, lo these >many years ago, that would isolate non standard telephone equipment from >the PSTN and still provide ringing and talk current to the non standard >equipment. Can anyone tell me whether such devices still exist and what >they are called? Protective Connecting Arrangement or Voice Connecting Arrangement. Popular varieties that went directly from a POTS line to the answering equipment included Universal Service Ordering Codes RDL RDM RDMZR RDY. Go look up BSP's under those codes. 463-340-101 covers the RDMZR, 463-340-110 and 463-340-111 cover the RDL and RDM There is an index up at http://www.telephonecollectors.org/DocumentLibrary/BSPs/463Division/463-000-000-Index.pdf There may still be a pile lurking in a warehouse (Sandman?) but since Carterfone (1968) and Type Acceptance nobody needs them. >***** Moderator's Note ***** > >There were a variety of interface devices that were made available >after the FCC mandated interconnection. I'm most familiar with the >CDH, which was intended to connect POTS lines to customer provided >equipment. It did the job, but it was too complicated: not only did it >have separate supervision leads that were isolated from the talk path, >but it had separate ringing leads as well. There might have been PBX's >or other CPE which could access the CDH directly, but ordinary key >equipment could not: to use it for CPE key equipment, you needed >_another_ interface to match the CDH interface. > >Ma Bell had too many interfaces and they cost too much to install and >rent: it was inevitable that the FCC would dictate type-acceptance and >allow direct connections. I don't remember when that happended, but it's >been the norm ever since. It would have been nice if they made Couplers that transparently passed the line and ring voltages through, as if they weren't there. I suspect the hidden strategy was to make CPE connections as difficult and expensive as possible, so customers would give up and lease Telco equipment for that nice recurring monthly charge. The Couplers were a pain to get from the Telco because you had to find a CSR who knew how to order them, and certain models were in short supply toward the end. And expensive to lease for what they were. But they eliminated the threat of immediate disconnection for 'attaching foreign equipment' to Ma Bell's lines. And while they were a pain for POTS voice work, they actually made building and running a Dial-A-Joke (Guilty...) or a movie theatre "Today's Shows and Showtimes" line easier. The coupler gave you dry closures for ring voltage and line supervision status, you gave the coupler dry closures for off-hook and on-hook commands, fed it your outgoing program audio at the right levels, and it did the rest. You only needed a tape player or two as program source with a half-watt or so speaker level output, a power supply, relays, pilot lamps, switches and a call counter to build the machine. --<< Bruce >>-- ------------------------------ Date: Fri, 24 Jul 2009 21:38:54 -0700 From: Thad Floryan <thad@thadlabs.com> To: redacted@invalid.telecom.csail.mit.edu Subject: iPhone 3Gs encryption cracked in two minutes Message-ID: <4A6A8C5E.5030800@thadlabs.com> Two telecom blurbs on Slashdot in one day: http://it.slashdot.org/story/09/07/24/2218201/iPhone-3Gs-Encryption-Cracked-In-Two-Minutes "In a Wired news article, iPhone Forensics expert Jonathan Zdziarski explains how the much-touted hardware encryption of the iPhone 3Gs is but a farce, and demonstrates how both the passcode and backup encryption can be bypassed in about two minutes. Zdziarski also goes on to say that all data on the iPhone - including deleted data - is automatically decrypted by the iPhone when it's copied, allowing hackers and law enforcement agencies alike [to] access the device's raw disk as if no encryption were present. A second demonstration features the recovery of the iPhone's entire disk while the device is still passcode-locked. According to a similar article in Ars Technica, Zdziarski describes the iPhone's hardware encryption by saying it's 'like putting privacy glass on half your shower door.' With the iPhone being sold into 20% of Fortune-100s and into the military, just how worried should we be with such shoddy security?" ------------------------------ Date: Sat, 25 Jul 2009 04:39:30 +0000 (UTC) From: wollman@bimajority.org (Garrett Wollman) To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <h4e2a2$2ibt$1@grapevine.csail.mit.edu> In article <XNCdndx3epUaavTXnZ2dnUVZ_vqdnZ2d@posted.nuvoxcommunications>, Robert Bonomi <bonomi@host122.r-bonomi.com> wrote: >That's right. it _is_ *outside* the official FM band. *NOBODY* can, or >_ever_could_ get a license for an audio-only FM transmitter on [87.75 MHz] Sure they can/could -- so long as they called it "low power TV". Near as I can tell from examination of the FCC rules, there is no requirement for an LPTV licensee to actually transmit a video signal. >In point of actual fact the TV station didn't broadcast on _that_ frequency >either. TV stations broadcast a single, _complex_, signal -- an amplitude- >modulated, single-sideband, vestigial carrier signal, to be precise Actually, a reduced-carrier, vestigial-sideband signal, to be accurate as well as precise. >-- one >component of which is a medium-deviation frequency-modulated 5.75 MHz 'tone'. Not really. The standard design for full-power analog TV transmitters over the past six decades has been to modulate and amplify the audio carrier separately and combine them after the final amplifier. This allows the audio carrier to be amplified using a more efficient (nonlinear) class-C amplifier. >The -only- reason it works, _when_ it does, is 'cheap manufacturing' of the >receiving devices. Nonsense. 87.7 MHz is in the European FM band, so most tuners can receive it. (In the UK, for example, it is used for "restricted service licence" transmitters at special events.) -GAWollman -- Garrett A. Wollman | The real tragedy of human existence is not that we are wollman@csail.mit.edu| nasty by nature, but that a cruel structural asymmetry Opinions not those | grants to rare events of meanness such power to shape of MIT or CSAIL. | our history. - S.J. Gould, Ten Thousand Acts of Kindness ------------------------------ Date: Sat, 25 Jul 2009 13:36:28 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <srWdnR0ldoExzfbXnZ2dnUVZ_jSdnZ2d@posted.nuvoxcommunications> In article <h4e2a2$2ibt$1@grapevine.csail.mit.edu>, Garrett Wollman <wollman@bimajority.org> wrote: >In article <XNCdndx3epUaavTXnZ2dnUVZ_vqdnZ2d@posted.nuvoxcommunications>, >Robert Bonomi <bonomi@host122.r-bonomi.com> wrote: > >> That's right. it _is_ *outside* the official FM band. *NOBODY* >> can, or _ever_could_ get a license for an audio-only FM transmitter >> on [87.75 MHz] > > Sure they can/could -- so long as they called it "low power TV". > Near as I can tell from examination of the FCC rules, there is no > requirement for an LPTV licensee to actually transmit a video > signal. They've still got to transmit it as a TV 'format' signal. Yeah, there's no requirement for any video 'content', per se -- I'd have [to] dig deep in the specs, but I suspect that something with the requisite framing (blanking, retrace, etc.) is required. >> In point of actual fact the TV station didn't broadcast on _that_ frequency >> either. TV stations broadcast a single, _complex_, signal -- an amplitude- >> modulated, single-sideband, vestigial carrier signal, to be precise > > Actually, a reduced-carrier, vestigial-sideband signal, to be accurate > as well as precise. WUPS! You're right. A little bit of bit-rot in the organic memory modules, apparently. ***** Moderator's Note ***** In one respect , you're both right: some TV transmitters were built to generate a composite video/aural signal at low levels, and then to amplify it all at once; others used separate video and aural chains, which were then shoved into a "Combiner", which is a _very_ expensive set of filters that kept the aural and video transmitters from destroying each other. I can't remember if a Combiner is technically a duplexer or a diplexer, but I'm sure that some stations didn't use them. For certain combinations of channel, power, and antenna, it was probably cheaper to do without the combiner and use linear amplifiers. BTW, I always thought that the "vestigial" sideband was the LOWER video sideband, which was chopped off at ~1.25 MHz. I didn't know the upper sideband required filtering as well: I always thought that it was limited by the video resolution and didn't need filtering. ------------------------------ Date: Sat, 25 Jul 2009 07:29:07 -0700 (PDT) From: Neal <nmclain@annsgarden.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <94bcf212-0c0a-45cc-96e4-7059a1b17ac2@d4g2000yqa.googlegroups.com> On Jul 24, 9:59 pm, bon...@host122.r-bonomi.com (Robert Bonomi) wrote: > In article <b4b3fbf9-2dd6-41db-9c90-700d62985...@q11g2000yqi.googlegroups.com>, > > > >  <hanco...@bbs.cpcn.com> wrote: > >On Jul 22, 11:58 pm, Neal McLain <nmcl...@annsgarden.com> wrote: > > >>  > On another newsgroup I was disappointed that correspondents strongly > >>  > supported the _bureaucratic_ reasons "it can't be done", even though > >>  > _physically/technically_ it certainly can be done. > > >> If by "it", you mean simultaneous transmission of a TV audio signal on > >> an FM carrier in the FM broadcast band, sure it can be done.  Any TV > >> station can apply for an FM license for that purpose.  And if it can > >> prove to the FCC that such an authorization is in the "public interest, > >> convenience, and necessity," it might even be able to get it. > > >My feeling is that since they broadcast audio on 87.7 FM a few weeks > >ago, they should continue to be able to broadcast audio on 87.7 FM now > >_without_ jumping through numerous licensing hoops to be allowed to do > >so. > > Why should they get any such _special_treatment_? > > Do you believe that -every- Television broadcast station should > continue to be able to broadcast audio at the sub-carrier frequency > of their old Analog license? > > >Or are you saying that there's another organization chumping at the > >bit to broadcast FM at 87.7, and, that frequency is far enough away > >from others, and, usable?  (Some other people suggested 87.7 actually > >isn't 'truly' on the FM dial being too low, but dials get it anyway.) > > That's right.  it _is_ *outside* the official FM band.   *NOBODY* > can, or _ever_could_ get a license for an audio-only FM transmitter > on that frequency. > > In point of actual fact the TV station didn't broadcast on _that_ > frequency either.   TV stations broadcast a single, _complex_, > signal -- an amplitude- modulated, single-sideband, vestigial > carrier signal, to be precise -- one component of which is a > medium-deviation frequency-modulated 5.75 MHz 'tone'. > > By 'sheer coincidence' -- since -this- 'tone' (technically a > "sub-carrier") is of constant amplitude -- it "looks" similar enough > to a conventional broadcast band FM signal that a conventional FM > receiver can extract the audio from it. > > There is _NO_ guarantee that -any- particular "FM broadcast band" > receiver will, in actuality, be able to tune 'far enough'  outside > the FM broadcast band to pick up that broadcast. > > > The -only- reason it works, _when_ it does, is 'cheap manufacturing' > of the receiving devices. > > >***** Moderator's Note ***** > > > Lisa, the FCC isn't likely to allow channel six to be used for FM > > broadcasting. Here's why: > > >1.  Sauce for the Goose, Sauce for the Gander: if the former holder > > of the Channel Six license gets to bring in revenue from FM   > > broadcasting, then the former holders of other channels are   > > entitled to do it too. > > And, the FCC does _not_ regulate radio use at the Newfoundland > aviation facility that was the traditional starting point for > trans-Atlantic flights via Thule, Greenland. > > Thus, no sauce for Gander.  (unless the Canadians order it,  it's > _their_ base :) > > > >2.  It's true that NTSC TV stations broadcast their audio using FM, > >    but they're only allowed to use 25 Kilohertz deviation, not the > >    75 KHz which is standard in the FM broadcast band. That's why > >    when listerners tuned their FM radios to Channel Six's audio, > >    it would always sound quieter than regular FM broadcasts: NTSC > >    is a different system, with different design criteria, and is > >    not suited to the transmission of high-fidelity music. > > Robert "The Punctuator" Bonomi wrote: > > In point of actual fact the TV station didn't broadcast on > _that_ frequency either. TV stations broadcast a single, > _complex_, signal -- an amplitude- modulated, single-sideband, > vestigial carrier signal, to be precise -- one component of > which is a medium-deviation frequency-modulated 5.75 MHz > 'tone'. Actually, the aural carrier is a discreet frequency-modulated carrier located 4.5 MHz above the visual carrier. The upper sideband of the visual carrier is cutoff-filtered at 4.2 MHz to avoid interference with the aural carrier. The aural carrier is phaselocked to the visual carrier to maintain a precise 4.5-MHz spacing between the two carriers. This is shown graphically in the Wikipedia article at http://en.wikipedia.org/wiki/NTSC#Transmission_modulation_scheme The 4.5-MHz offset between the two carriers simplifies the design of television receivers. Since the aural carrier is always 4.5 MHz above the visual carrier, the audio detection circuits can be fix-tuned to that frequency. Most receivers sold during the earlier years of the industry used this "intercarrier" design. This technique also works if the 4.5-MHz aural carrier is *below* the visual carrier. In 1975, Time, Inc. launched its fledgling pay-TV service called "Home Box Office" (HBO) by satellite. Over the next few years, CATVs across the nation started carrying it, and numerous manufacturers came out with devices to secure it from unauthorized reception by basic-only subscribers. One manufacturer came up with the bright idea of inverting the channel, with aural below visual. It offered a midband modulator (channel 17 as I recall) to generate the inverted channel, and a simple settop box that reinverted the channel back to normal and converted it to a standard VHF frequency. It quickly became obvious that inverting the channel was not a secure scrambling technique. Intercarrier TV sets (which, in those days, accounted for the vast majority of consumer sets) demodulated the audio just fine. That left CATVs with only one line of defense against signal theft: the fact that HBO was carried in the midband, out of tuning range for the 12-channel TV sets of the day. But those TV sets all had "turret" tuners -- those big clunky things that switched different circuit boards into the circuit, one for each channel. It didn't take long for local TV shops to start offering "Free HBO" circuit boards. Neal McLain ***** Moderator's Note ***** I lived in Santa Barbara, California during 1978 and 1979, and the cable TV company had a "Channel 100" service, which was one of the early "closed system" offerings. The actual frequency used was just below TV channel 7, in the public safety/industrial band usually used by taxicabs, police, and fire departments. "Channel 100" was from 168 to 174 MHz, just below VHF TV Channel 7 IIRC. Since Channel 7 wasn't in use on the cable system, the local TV shops started to modify sets so that Channel 7 was actually "Channel 100": all they had to do was squeeze the inductor on the turret tuner, so that it would cover the lower range. The cable company was understandably upset, but the modification became common knowledge, so they had to add an interfering signal to the Channel 100 frequency band, and then give out filters to Channel 100 subscribers to notch out the interference and restore the channel to viewable condition. Of course, the local ham club had a contest to see who could design the best "Channel 100" filter, and they came up with a coaxial cavity model, constructed from copper pipe, which did a better job than the "LC" filters provided by the cable company! Persons who will not be named took it on themselves to start a cottage industry, manufacturing and distributing channel 100 filters. Said persons soon discovered that the available market was limited because they depended on word-of-mouth advertising, and abandoned the effort. By the time I had migrated to Boston and taken up residence next to Northeastern University, where I was attending, HBO had become prominent, and it was using the Multi-point Distribution System to send signals to local cable head-ends. Once again, ham operators found a way: a common child's toy of the day - a circular snow slide - turned out to make an excellent parabola for a ~2 GHz dish receiver. As it happened, I didn't have a line-of-sight to the Prudential tower, where HBO's transmitter was, but I found out that the building across the street made an excellent near-field reflector. Stiller and Mira never looked so good. Of course, everything finally went to satellite, so only those who could afford TeleVision Receive Only (TVRO) satellite receivers, and who had space for them, could get it directly. Since cable TV took a while to get to rural areas, the 3-meter-diameter dishes soon became known as "The <fill in your state here> State Flower", and their popularity gave HBO another problem, which was that satellite TV receivers, already equipped with Polar mounts that could track any bird in the Clarke Belt, could poach their signal. Inevitably, scrambling became the norm, and now the few remaining satellite receivers still in use are limited to viewing occasional TV feeds from news crews at special events, back-hauls of network traffic, and some specialized programming, such as medical training films and over-the-air classroom shows intended for Alaska or other remote regions. Interestingly enough, there's a ham connection in TVRO as well: one of the better-known firms in the field is the R.L. Drake Company of Miamisburg, Ohio, which used to manufacture a line of Amateur radio transmitters, receivers, and transceivers. The sets are still prized for their excellent audio quality and layout - yours truly owns a Drake TR-4 - although they're also in demand by "Outbanders", the citizens-band operators who modified old ham gear to operate in the relatively quiet areas beyond the official CB frequencies. Ah, the memories. Bill Horne ------------------------------ Date: Sat, 25 Jul 2009 03:55:04 -0700 (PDT) From: Neal <nmclain@annsgarden.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <72addffe-9ac3-4be0-bb03-30dd3f81f26d@b14g2000yqd.googlegroups.com> On Jul 24, 7:54 am, hanco...@bbs.cpcn.com wrote: > On Jul 22, 11:58 pm, Neal McLain <nmcl...@annsgarden.com> wrote: > > >  > On another newsgroup I was disappointed that correspondents strongly > >  > supported the _bureaucratic_ reasons "it can't be done", even though > >  > _physically/technically_ it certainly can be done. > > > If by "it", you mean simultaneous transmission of a TV audio signal on > > an FM carrier in the FM broadcast band, sure it can be done.  Any TV > > station can apply for an FM license for that purpose.  And if it can > > prove to the FCC that such an authorization is in the "public interest, > > convenience, and necessity," it might even be able to get it. > > My feeling is that since they broadcast audio on 87.7 FM a few weeks > ago, they should continue to be able to broadcast audio on 87.7 FM now > _without_ jumping through numerous licensing hoops to be allowed to do > so. > > Or are you saying that there's another organization chumping at the > bit to broadcast FM at 87.7, and, that frequency is far enough away > from others, and, usable?  (Some other people suggested 87.7 actually > isn't 'truly' on the FM dial being too low, but dials get it anyway.) > > Another poster noted radio stations aren't as valuable as they used to > be.  In the Philadelphia market there has been a fair amount of > turnover and format changes.  A few stations seemed to take in very > "low-end" advertisements (semi-scams, such as miracle health > supplements) That seems to me to indicate there isn't as much value to > the station because they're desperate to take crappy ads. > > ***** Moderator's Note ***** > > Lisa, the FCC isn't likely to allow channel six to be used for FM > broadcasting. Here's why: > > 1.  Sauce for the Goose, Sauce for the Gander: if the former holder of >     the Channel Six license gets to bring in revenue from FM >     broadcasting, then the former holders of other channels are >     entitled to do it too. > > 2.  It's true that NTSC TV stations broadcast their audio using FM, >     but they're only allowed to use 25 Kilohertz deviation, not the 75 >     KHz which is standard in the FM broadcast band. That's why when >     listerners tuned their FM radios to Channel Six's audio, it would >     always sound quieter than regular FM broadcasts: NTSC is a >     different system, with different design criteria, and is not >     suited to the transmission of high-fidelity music. hancock4@bbs.cpcn.com wrote: > My feeling is that since they broadcast audio on 87.7 FM a few weeks > ago, they should continue to be able to broadcast audio on 87.7 FM > now _without_ jumping through numerous licensing hoops to be allowed > to do so. (a) I don't think WPVI-DT's competitors would agree. (b) WPVI's owners (The Walt Disney Company) would not be able to obtain a license to broadcast an FM signal at 87.7 (or 87.75) no matter how many "numerous licensing hoops" it jumped through. (c) Even if it could, it wouldn't want to. A carrier at that frequency would interfere with (i.e., utterly destroy) the WPVI-DT signal now operating on Channel 6. > Or are you saying that there's another organization chumping at the > bit to broadcast FM at 87.7, and, that [that] frequency is far enough > away from others, and, usable? WPVI-DT operates on the same Channel 6 that WPVI-TV formerly used. But the audio signal is now encoded digitally as part of the same digital stream that carries the video. There is no separate aural carrier at 87.75 MHz. See (c) above. > (Some other people suggested 87.7 actually isn't 'truly' on the FM > dial being too low, but dials get it anyway.) BINGO! That's precisely the point of this whole Channel 6 thread- within-a-thread. > Another poster noted radio stations aren't as valuable as they used > to be. In the Philadelphia market there has been a fair amount of > turnover and format changes. A few stations seemed to take in very > "low-end" advertisements (semi-scams, such as miracle health > supplements) That seems to me to indicate there isn't as much value > to the station because they're desperate to take crappy ads. Well, then, don't listen! For years, you've been making that same complaint about advertising-supported non-broadcast CATV channels. If you don't like the ads, don't watch the channel! Neal McLain ------------------------------ Date: Sat, 25 Jul 2009 03:13:15 -0700 (PDT) From: Neal <nmclain@annsgarden.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <cc3a27a8-e628-4449-9f09-1462f903d3a4@d4g2000yqa.googlegroups.com> On Jul 24, 10:01 pm, bon...@host122.r-bonomi.com (Robert Bonomi) wrote: > In article <MPG.24d263d36599fa5d989...@news.eternal-september.org>, > > T  <kd1s.nos...@cox.nospam.net> wrote: > > [sneck] > > > > > > >Not to mention that channel 6 video sat right in the 6m band. > > >***** Moderator's Note ***** > > >The Six-Meter Amateur band is from 50 to 54 Megahertz. The old TV > >Channel 6 was from 82 to 88 Megahertz. Since the FCC once sent me a > >letter about a Television Interference complaint from a man who lived > >a block or two away from me, I remember having to look up the TV > >assignments - pre internet, mind you, when we had libraries that were > >only open during snowstorms - and calculating the harmonics of my > >Eight megahertz oscillator to diagnose the problem. > > >Long story short, I don't think TV Channel 6's video is near the Six > >Meter ham band. > > Channel _one_, back when it existed, included the upper half of the > spectrum now allocated for 6m amateur operations. > > ***** Moderator's Note ***** > > What was Channel one's allocation? When was it discontinued, and for > what purpose? > > Bill Horne Bill: Here's the definitive Channel 1 story, written by John W. Reiser, former Chief of the International Bureau of the FCC: http://www.tech-notes.tv/History&Trivia/Channel%20One/Channel_1.htm Neal McLain ------------------------------ Date: Sat, 25 Jul 2009 08:19:30 -0700 (PDT) From: "harold@hallikainen.com" <harold@hallikainen.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <8312d424-b6ed-41dc-8818-dbba68d28117@k13g2000prh.googlegroups.com> > ***** Moderator's Note ***** > > What was Channel one's allocation? When was it discontinued, and for > what purpose? > > Bill Horne Some history of channel one, written by a former FCC staff member, is at http://louise.hallikainen.org/BroadcastHistory/index.php/What%20Ever%20Happened%20to%20Channel%201 . Harold ------------------------------ Date: Sat, 25 Jul 2009 14:14:15 -0700 (PDT) From: Neal <nmclain@annsgarden.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <d518340f-673e-4df2-9b26-3f87b96cb5a9@d4g2000vbm.googlegroups.com> On Jul 25, 12:09 pm, "har...@hallikainen.com" <har...@hallikainen.com> wrote: > > ***** Moderator's Note ***** > > > What was Channel one's allocation? When was it discontinued, and for > > what purpose? > > > Bill Horne > > Some history of channel one, written by a former FCC staff member, is at > > http://louise.hallikainen.org/BroadcastHistory/index.php/What%20Ever%20Happened%20to%20Channel%201 > > Harold Since Harold Hallikainen and I both cited the same "Whatever Happened to Channel 1" article by John W. Reiser, I'd like say a few words about John. I worked for John during the 1950s when I was attending the University of Michigan in Ann Arbor. During the regular University academic year, John was Chief Engineer at the Speech Department's Television Studio, a lab studio for training television production. It wasn't much of a studio -- just a classroom with a couple of monochrome vidicon cameras. But it did give students a chance to practice before live cameras, and to learn elementary production techniques. I was sort of John's assistant, mostly assigned to setting up equipment for classes, and "shading cameras" during class. In those days, "shading cameras" was an important function because video cameras didn't have any of the automatic brightness/contrast adjustment features now common. I spent many an hour sitting there tweaking signal levels during class sessions. During the summers, John was Chief Engineer at the Radio Department at the National Music Camp in Interlochen. The Department's job was to record every major concert or recital performed by campers (students) or faculty. We assembled broadcast programs from these recordings (shipped to radio stations worldwide); made LP recordings of select performances for sale to campers (or their parents); ran PA systems for public functions; and maintained all sorts of electronic gear. I was one of a group of college guys that spent several summers as radio engineer at the Camp. Pay wasn't very good, but the job included room, board, and free use of recreational facilities. The camp was located between two lakes (hence the name Interlochen), so there was an endless variety of water sports. And then there were all those female college students... uh, I guess I better stop here. Anyway, that's how I spent most of my college years: working for John in Ann Arbor during the academic year and working summers for John at Interlochen. The last time I saw John was at the 1995 Society of Broadcast Engineers Convention in New Orleans, where John was guest speaker at the Awards Banquet. I wasn't sure he'd remember me, but indeed he did, and he even acknowledged my presence in the audience during his talk. The Quarter Century Wireless Association has a bio of John at http://www.qcwa.org/wq4l.htm Neal McLain ------------------------------ Date: Sat, 25 Jul 2009 07:43:06 -0700 From: AES <siegman@stanford.edu> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Wireless speed loss Message-ID: <siegman-7ADB71.07423625072009@news.stanford.edu> In article <h4do26$177$1@news.eternal-september.org>, Steven Lichter <diespammers@killspammers.com> wrote: > I just had some major problems involving my Airport card and the DSL > Wireless Hub/modem. > > A couple of weeks ago a at&t contractor was checking cable pairs to > make sure that they match the records; we all know that there are a lot > of errors; anyway he moved me over to the cable pair that his records > showed, the problem was the cable he moved me to had a dead short; i.e. no > phone or DSL for 4 days, they got that fixed but my speed was down Sympathies! -- that's what happens! > really bad. They found 2 bridge taps on my cable; I guess DSL does not > like those, they removed them and my speed came back up a great deal, but I got DSL about 9 years ago (I'm 25,000 feet from nearest CO and should never have been able to get it, but the subscription was through my university, which had clout with Pac Bell). Took about a year of repeated hassles to get all the bridge taps and stuff off the line; but once that was done, service was consistently slow but reliable for the next 8 years. > not what is was supposed to be. The strange thing is my ethernet > connected computer is working fine. I made no changes on either setup > and both were working fines before the repair from hell started. I do Your computer (at least if it's a Mac) is generally good at remembering all the needed setting, or else at searching automatically through options until things work. ------------------------------ Date: Sat, 25 Jul 2009 11:12:02 -0700 From: Steven Lichter <diespammers@killspammers.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Wireless speed loss Message-ID: <h4fiag$ah8$1@news.eternal-september.org> AES wrote: > In article <h4do26$177$1@news.eternal-september.org>, > Steven Lichter <diespammers@killspammers.com> wrote: > >> I just had some major problems involving my Airport card and the DSL >> Wireless Hub/modem. >> >> A couple of weeks ago a at&t contractor was checking cable pairs to >> make sure that they match the records; we all know that there are a lot >> of errors; anyway he moved me over to the cable pair that his records >> showed, the problem was the cable he moved me to had a dead short; i.e. no >> phone or DSL for 4 days, they got that fixed but my speed was down > > Sympathies! -- that's what happens! > >> really bad. They found 2 bridge taps on my cable; I guess DSL does not >> like those, they removed them and my speed came back up a great deal, but > > I got DSL about 9 years ago (I'm 25,000 feet from nearest CO and should > never have been able to get it, but the subscription was through my > university, which had clout with Pac Bell). Took about a year of > repeated hassles to get all the bridge taps and stuff off the line; but > once that was done, service was consistently slow but reliable for the > next 8 years. > >> not what is was supposed to be. The strange thing is my ethernet >> connected computer is working fine. I made no changes on either setup >> and both were working fines before the repair from hell started. I do > > Your computer (at least if it's a Mac) is generally good at remembering > all the needed setting, or else at searching automatically through > options until things work. > I started out with 3Meg DSL and it worked fine, I went to 6Meg when it was offered and after a little work by the phone company; removing all my filters from the phones and running a single pair to the DSL modem it worked constant between 4.9 and 5.7. on both machines. I'm told that part of the problem is I'm on an old section of lead cable which is 26 Ga wire, the rest of the cable is at 24 ga. As far as they can tell all the bridge taps are gone, a tech worked on it for several hours and then made sure that their cable records were corrected and placed a HI-Cap take on my line; not really a Hi-Cap but as he said any work on it will raise flags before they work on it. Sometime next year all the lead cable will be gone and we will be able t o get U-Verse. I will switch my DSL to that, but not my phone; I don't like the glass since the backup is less then an hour. I'm 10,000feet from the CO, but they really don't like 6 Meg over 7000 feet. There is a NT remote, but my line with the DSL is not in that system, but my second line is and I'm thinking of moving the DSL to that number, then I'll be less the 3000 from them. A contact with their HQ is working on getting it set up on that line without moving my current one; no cost to me if it make no difference, if it does work, the old one goes away and no further cost, they have been here over 15 times in the last 2 months. -- The only good spammer is a dead one!! Have you hunted one down today? (c) 2009 I Kill Spammers, inc, A Rot in Hell. Co. ------------------------------ Date: Sat, 25 Jul 2009 12:54:03 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: redacted@invalid.telecom.csail.mit.edu Subject: Re: What is this device called Message-ID: <856dnRlMe8wm2_bXnZ2dnUVZ_oCdnZ2d@posted.nuvoxcommunications> In article <QUnam.1071$MA3.310@nwrddc02.gnilink.net>, Tom Horne <hornetd@verizon.net> wrote: >> ***** Moderator's Note ***** >> >> There were a variety of interface devices that were made available >> after the FCC mandated interconnection. I'm most familiar with the >> CDH, which was intended to connect POTS lines to customer provided >> equipment. It did the job, but it was too complicated: not only did it >> have separate supervision leads that were isolated from the talk path, >> but it had separate ringing leads as well. There might have been PBX's >> or other CPE which could access the CDH directly, but ordinary key >> equipment could not: to use it for CPE key equipment, you needed >> _another_ interface to match the CDH interface. >> >> Ma Bell had too many interfaces and they cost too much to install and >> rent: it was inevitable that the FCC would dictate type-acceptance and >> allow direct connections. I don't remember when that happended, but it's >> been the norm ever since. > >Yes Bill, but that doesn't help with stuff that is not type accepted. >Isn't the new term of art certified? I'm trying to devise a way to >patch the PSTN incoming calls to manual switchboards that predate >customer dialing. If you connect the interconnect terminals of some >of those boards it will look like an off hook condition to the PSTN. If you'd said -that- in the first place, you'd have gotten better first-round answers. <grin> Anything 'off the shelf' in the (even semi-) modern world is going to require quite a it of custom 'glue' logic to adapt that cordboard to the weirdness of the CPE side of the adapter box. You may as well just get one of the (many) registered, type-accepted, 'FCC part 68' qualified, 'phone line interface integrated circuits (whew!!), and roll your required custom interfacing logic around -that-. Such chips are only a few dollars (at most), quantity one. ------------------------------ Date: Sat, 25 Jul 2009 14:00:44 -0400 From: tlvp <mPiOsUcB.EtLlLvEp@att.net> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Wireless speed loss Message-ID: <op.uxmxniyxo63xbg@acer250.gateway.2wire.net> On Fri, 24 Jul 2009 23:09:29 -0400, Steven Lichter <diespammers@killspammers.com> wrote: > I just had some major problems involving my Airport card and the DSL > Wireless Hub/modem. > > A couple of weeks ago a at&t contractor was checking cable pairs to > make sure that they match the records; we all know that there are a lot > of errors; anyway he moved me over to the cable pair that his records > showed, the problem was the cable he moved me to had a dead short; i.e. no > phone or DSL for 4 days, they got that fixed but my speed was down > really bad. They found 2 bridge taps on my cable; I guess DSL does not > like those, they removed them and my speed came back up a great deal, but > not what is was supposed to be. The strange thing is my ethernet > connected computer is working fine. I made no changes on either setup > and both were working fines before the repair from hell started. I do > know that there is a little loss on wireless connections, but not 1.3 on > a 6 meg link. I asked on the Mac groups, but no answers. I'm sure it > has something to do with my AirPort card and the Router, but as I said > no changes were made and all the setting are the same. > > There are other problems, like on 26 ga led cable, that AT&T plans to > replace some time next year when they plan on finally offering U-Verse > on my block, we are only block not to have it since our cable is over 30 > years old. If your AirPort is PCI-based, I have no idea. But if it's USB-based, perhaps the USB port it's on is working at USB 1.1 speeds rather than 2.0? Just a stab in the dark, of course :-) . Cheers, -- tlvp -- Avant de repondre, jeter la poubelle, SVP ------------------------------ Date: Sat, 25 Jul 2009 14:12:31 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Wireless speed loss Message-ID: <5f6dnTOm7siCxPbXnZ2dnUVZ_uOdnZ2d@posted.nuvoxcommunications> In article <h4do26$177$1@news.eternal-september.org>, Steven Lichter <diespammers@killspammers.com> wrote: > I just had some major problems involving my Airport card and the DSL > Wireless Hub/modem. > > A couple of weeks ago a at&t contractor was checking cable pairs to > make sure that they match the records; we all know that there are a > lot of errors; anyway he moved me over to the cable pair that his > records showed, the problem was the cable he moved me to had a dead > short; i.e. no phone or DSL for 4 days, One of the reasons residential DSL is so inexpensive -- *NO* service-level guarantees whatsoever. <wry grin> > They got that fixed but my speed was down really bad. They found 2 > bridge taps on my cable; I guess DSL does not like those, Very true. > ... they removed them and my speed came back up a great deal, but > not what is was supposed to be. The strange thing is my ethernet > connected computer is working fine. I made no changes on either > setup and both were working fines before the repair from hell > started. I do know that there is a little loss on wireless > connections, but not 1.3 on a 6 meg link. Well, unless you're running -really- ancient hardware, the wireless _should_ be running at 11mbit/sec., _minimum_. even allowing for the 'overhead' losses, this should easily swamp a 6mbit/sec upstream link. Thus, unless 'somehow' the Wi-Fi card, or the router have gotten 'locked down' to a slower bit-rate, that _shouldn't_ be the problem. > I asked on the Mac groups, but no answers. I'm sure it has > something to do with my AirPort card and the Router, but as I said > no changes were made and all the setting are the same. The -really- telling item is that the ethernet-connected machine is seeing full speed, while the wireless one is not. Possibilities boil down to:
  1. 'Something' is rate-limiting the wireless link, while not affecting the ethernet connection.
  2. 'Somehow', the wireless section has linked up at 'significantly less than maximum' rate, and _is_ the bottleneck.
  3. 'For some reason', the packet size on the wireless link has been set to a very small number, and packet 'overhead' is a disproportionately large part of the total data traffic.
  4. "Something else" is using that bandwidth -- a neighbor 'leeching' off the Wi-Fi connection maybe?
  5. 'Something' is hogging the CPU on the wireless machine. 'Viruses' that attack Macs are unusual, but they do exist. The coincidental timing makes it _really_ unlikely, but it's by no means certain that it such a coincidence did _not_ occur.
If you haven't tried it already, I'd try powering everything down, including the access-point, waiting a good 30 seconds, and then powering things back up again. Then see if the problem still persists. Next, disconnect everything else, and see if the wireless box still has the problem. Third, try the wireless box on an _ethernet_ link, with the wireless turned off. things like this will go a long ways towards 'localizing' the problem. ------------------------------ Date: Sun, 26 Jul 2009 10:27:30 +1000 From: David Clayton <dcstar@myrealbox.com> To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Wireless speed loss Message-ID: <pan.2009.07.26.00.27.28.939639@myrealbox.com> On Fri, 24 Jul 2009 23:09:29 -0400, Steven Lichter wrote: > I just had some major problems involving my Airport card and the DSL > Wireless Hub/modem. ....... > The strange thing is my ethernet connected computer > is working fine. I made no changes on either setup and both were working > fines before the repair from hell started. I do know that there is a > little loss on wireless connections, but not 1.3 on a 6 meg link. I asked > on the Mac groups, but no answers. I'm sure it has something to do with > my AirPort card and the Router, but as I said no changes were made and all > the setting are the same. ....... Try playing with the MTU settings on your ADSL and Wireless links (if possible). You also need to scrutinise the packet counters to see if there any any errors/dropped packets. -- Regards, David. David Clayton Melbourne, Victoria, Australia. Knowledge is a measure of how many answers you have, intelligence is a measure of how many questions you have. ------------------------------ Date: Sat, 25 Jul 2009 13:29:10 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <Ht2dnXPtQbZr0_bXnZ2dnUVZ_umdnZ2d@posted.nuvoxcommunications> In article <0bydndQEGcGrbPTXnZ2dnUVZ_oNi4p2d@posted.nuvoxcommunications>, Robert Bonomi <bonomi@host122.r-bonomi.com> wrote: >> >>***** Moderator's Note ***** >> >>Long story short, I don't think TV Channel 6's video is near the Six >>Meter ham band. >> > >Channel _one_, back when it existed, included the upper half of the spectrum >now allocated for 6m amateur operations. Note: I have to correct myself. At one point, Channel _2_ sat on what is now the entire 6m ham band. Then Channel 1 occupied those frequencies for a while. Then it was moved below 50 MHz. (making life more fun, this was all 'shared use' spectrum. :) Then channel 1 'went away' (the 'easiest' way to avoid having to 'renumber' the other channels). > >***** Moderator's Note ***** > >What was Channel one's allocation? When?? *GRIN* It (and the other VHF channels -- did you know that there were _VHF_ channels up to 'channel _19_' at one time?) moved around. 'Gory details' in the Wiki article cited below. Channel 1 was moved from it's original assignment (44-50MHz) to 50-56MHz, to make room for the original 'FM broadcast band'. This was 1940. > When was it discontinued? That's easier. May, 1948. However, thy were out of the now 6m Ham frequencies in 1946. > and for what purpose? In modern parlance, to 'rationalize' spectrum usage. :) *LOTS* of stuff was moved around at that time. TV spectrum got juggled in 1940, 1946, _and_ 1948 (minor tweak). the '46 changes gave us the current channel allocations, '48 gave TV the -exclusive- use of that spectrum space (and eliminated channel 1). See the Wikipedia :) http://en.wikipedia.org/wiki/Channel_1 ------------------------------ Date: Sat, 25 Jul 2009 18:13:41 -0700 (PDT) From: hancock4@bbs.cpcn.com To: redacted@invalid.telecom.csail.mit.edu Subject: Re: Walter's Telephones Message-ID: <ffdad5b5-e6c2-44c7-8cab-8edf11b13bfc@p23g2000vbl.googlegroups.com> On Jul 24, 10:59 pm, bon...@host122.r-bonomi.com (Robert Bonomi) wrote: >> My feeling is that since they broadcast audio on 87.7 FM a few >> weeks ago, they should continue to be able to broadcast audio on >> 87.7 FM now _without_ jumping through numerous licensing hoops to >> be allowed to do so. > > Why should they get any such _special_treatment_? There is no "special" treatment, per the circumstances described in prior posts.. > Do you believe that -every- Television broadcast station should > continue to be able to broadcast audio at the sub-carrier frequency > of their old Analog license? IRELEVENT. We are talking about ONE SPECIFIC channel. > That's right.  it _is_ *outside* the official FM band.   *NOBODY* > can, or _ever_could_ get a license for an audio-only FM transmitter > on that frequency. > > In point of actual fact the TV station didn't broadcast on _that_ > frequency either.   TV stations broadcast a single, _complex_, > signal -- an amplitude- modulated, single-sideband, vestigial > carrier signal, to be precise -- one component of which is a > medium-deviation frequency-modulated 5.75 MHz 'tone'. > > By 'sheer coincidence' -- since -this- 'tone' (technically a > "sub-carrier") is of constant amplitude -- it "looks" similar enough > to a conventional broadcast band FM signal that a conventional FM > receiver can extract the audio from it. Doesn't matter. > There is _NO_ guarantee that -any- particular "FM broadcast band" > receiver will, in actuality, be able to tune 'far enough'  outside > the FM broadcast band to pick up that broadcast. > The -only- reason it works, _when_ it does, is 'cheap manufacturing' > of the receiving devices. The audio portion of TV's Channel 6 was receivable on any FM radio, either cheap ones or good ones, tube or IC, for _decades_. The _only_ issue that could matter is if someone else desires use of that particular frequency. Others have said it cannot be used because it would cause interference to other FM stations close in frequency. ------------------------------ TELECOM Digest is an electronic journal devoted mostly to telecom- munications topics. It is circulated anywhere there is email, in addition to Usenet, where it appears as the moderated newsgroup 'comp.dcom.telecom'. TELECOM Digest is a not-for-profit, mostly non-commercial educational service offered to the Internet by Patrick Townson. All the contents of the Digest are compilation-copyrighted. You may reprint articles in some other media on an occasional basis, but please attribute my work and that of the original author. The Telecom Digest is currently being moderated by Bill Horne while Pat Townson recovers from a stroke. Contact information: Bill Horne Telecom Digest 43 Deerfield Road Sharon MA 02067-2301 781-784-7287 bill at horne dot net Subscribe: telecom-request@telecom-digest.org?body=subscribe telecom Unsubscribe: telecom-request@telecom-digest.org?body=unsubscribe telecom This Digest is the oldest continuing e-journal about telecomm- unications on the Internet, having been founded in August, 1981 and published continuously since then. Our archives are available for your review/research. We believe we are the oldest e-zine/mailing list on the internet in any category! URL information: http://telecom-digest.org Copyright (C) 2009 TELECOM Digest. All rights reserved. Our attorney is Bill Levant, of Blue Bell, PA. ************************ --------------------------------------------------------------- Finally, the Digest is funded by gifts from generous readers such as yourself who provide funding in amounts deemed appropriate. Your help is important and appreciated. A suggested donation of fifty dollars per year per reader is considered appropriate. See our address above. Please make at least a single donation to cover the cost of processing your name to the mailing list. All opinions expressed herein are deemed to be those of the author. Any organizations listed are for identification purposes only and messages should not be considered any official expression by the organization. End of The Telecom digest (19 messages) ******************************

Return to Archives**Older Issues