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The Telecom Digest for November 12, 2010 Volume 29 : Issue 305 : "text" Format Messages in this Issue: History--computer based information operator terminal system (Lisa or Jeff) Re: History--computer based information operator terminal system (Richard) California phone rates rising (Thad Floryan) Re: Why is T-1 24 Channels? (R. T. Wurth) Re: early CATV, was: Bell System Technical Journal, 1922-1983 (Neal McLain) Re: early CATV, was: Bell System Technical Journal, 1922-1983 (John Mayson) Re: early CATV, was: Bell System Technical Journal, 1922-1983 (Robert Bonomi) Early cable TV competition (was Re: early CATV (was: BSTJ ...)) (jsw) Re: Bell System Technical Journal, 1922-1983 (Eric Tappert) Re: early CATV, was: Bell System Technical Journal, 1922-1983 (Eric Tappert) Re: Happy anniversary cellphone! (tlvp) Re: Happy anniversary cellphone! (John Mayson) Re: Why is T-1 24 Channels? (Fred Goldstein) Users as Toast: The Blocking of Google TV (Monty Solomon) Update: How They're Blocking Google TV (with Screenshots) (Monty Solomon) Re: Bell System Technical Journal, 1922-1983 (Richard) Re: T-Mobile 4G commercials (Cecile) ====== 28 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: Wed, 10 Nov 2010 13:56:40 -0800 (PST) From: Lisa or Jeff <hancock4@bbs.cpcn.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: History--computer based information operator terminal system Message-ID: <cd519a85-1407-4931-999b-fc7b0dda7e13@h21g2000vbh.googlegroups.com> A history article in the IBM Systems Magazine describes an IBM System/ 360-50 used to support an on-line lookup system for telephone information operators. While the article is more about the computer than the telephone operators, it is interesting none the less. for article please see: http://www.ibmsystemsmag.com/mainframe/marchapril09/24886p1.aspx (consists of three pages). (That web page has other mainframe computer history stories.) Date: Thu, 11 Nov 2010 11:09:02 -0800 From: Richard <rng@richbonnie.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: History--computer based information operator terminal system Message-ID: <6efod69qm4e8kd7ftqov9rjsgfkt5sle4k@4ax.com> On Wed, 10 Nov 2010 13:56:40 -0800 (PST), Lisa or Jeff <hancock4@bbs.cpcn.com> wrote: >A history article in the IBM Systems Magazine describes an IBM System/ >360-50 used to support an on-line lookup system for telephone >information operators. While the article is more about the computer >than the telephone operators, it is interesting none the less. > >for article please see: >http://www.ibmsystemsmag.com/mainframe/marchapril09/24886p1.aspx >(consists of three pages). > >(That web page has other mainframe computer history stories.) Sometime in my career at Bell Labs (I think in the 1970's, but not sure) our internal newspaper announced a new completely automatic directory-assistance system they were experimenting with. They had it working with the employee phone directory. To use it, you used the telephone keypad to spell out the last name of the person wanted. I don't know if this ever got into production. Date: Wed, 10 Nov 2010 22:55:54 -0800 From: Thad Floryan <thad@thadlabs.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: California phone rates rising Message-ID: <4CDB937A.9090705@thadlabs.com> The last half of Dave Lazarus' latest column about health care costs has this interesting addendum: <http://www.latimes.com/health/la-fi-lazarus-20101109,1,5980772.column> [...] Phone rates rising The consumer-watchdog division of the California Public Utilities Commission is calling on regulators to extend price caps for basic residential phone rates. Limits on how much rates can go up will end Jan. 1. A recent report by the commission's Division of Ratepayer Advocates concluded that deregulation of California's phone market hasn't resulted in increased competition and, instead, has led to higher prices for various services. "Lifting the price caps on ancillary services has served only to raise rates for consumers," said Joe Como, the division's acting director. "The same will happen to basic rates on Jan. 1 unless the CPUC acts now to protect consumers who depend on affordable phone service." A separate report by California's Senate Office of Oversight and Outcomes found that state regulators have largely ignored the telecom market after declaring four years ago that sweeping deregulation would usher in a new era of market competition and lower prices for consumers. According to the report, AT&T and Verizon control 85% of all land lines statewide and 65% of telecom services in general -- about the same market share they held before deregulation. Meanwhile, prices for some services, such as having an unlisted phone number, have soared by as much as 600%. Como said the commission should maintain limits on price hikes for basic residential phone service "until the CPUC sets rules that will result in reasonable and affordable rates." A spokeswoman for the commission said it would review the division's request. In the meantime, don't hold your breath. Date: Wed, 10 Nov 2010 05:00:58 +0000 (UTC) From: "R. T. Wurth" <rwurth53@verizon.net> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Why is T-1 24 Channels? Message-ID: <Xns9E2C2C2D23Brwurth53verizonnet@188.40.43.230> Either a guess or a vague recollection, I'm not sure which: The old analog mux hierarchy was based on a first-level of 24 to 1 multiplexing, and T1's designers wanted to keep the same office layout and cabling rules that grouped 24 pairs together between switching gear, transmission gear, and patch panels. -- Rich Wurth Rumson, NJ USA ***** Moderator's Note ***** WE HAVE A WINNER! They did such a good job of keeping the existing stuff in place that you'd see the same "J" number on the side of an "N" Carrier bank as was on a "T" carrier D1 bank: it was the same mounting shelf. Bill Horne Moderator Date: Wed, 10 Nov 2010 12:09:49 -0800 (PST) From: Neal McLain <nmclain@annsgarden.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: early CATV, was: Bell System Technical Journal, 1922-1983 Message-ID: <de342572-c8ec-4a42-b03b-41de3fac6ba4@v19g2000yqa.googlegroups.com> On Nov 9, 6:48 pm, danny burstein <dan...@panix.com> wrote: > In <4CD8E573.6060...@annsgarden.com> Neal McLain <nmcl...@annsgarden.com> writes: > > >Now here's my trivia question: how many channels did the first cable TV > >system carry? > > The first "cable tv system", or the first "community antenna tv system"? > And are you referring to the US, or including the rest of the world? > > -- > _____________________________________________________ > Knowledge may be power, but communications is the key > dan...@panix.com > [to foil spammers, my address has been double rot-13 encoded] The first cable TV systems were community antenna tv systems. For the first 25 years of the industry's existence, broadcast retransmission (especially distant stations) was about the only thing they had to sell. Many systems originated local programming ("local origination") and carried PEG (public, educational, and government) access programming, but these services didn't sell many subscriptions. The term CATV originally stood for community antenna TV. Somewhere around the mid-70s, when CATV companies began carrying satellite- delivered non-broadcast programming, the term CATV morphed into cable TV. So the question refers to the first CATV system. As for your second question, I was thinking of the US, but the question could certainly apply worldwide. Neal McLain Date: Thu, 11 Nov 2010 08:50:30 -0600 (Central Standard Time) From: John Mayson <john@mayson.us> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: early CATV, was: Bell System Technical Journal, 1922-1983 Message-ID: <alpine.WNT.2.00.1011110844130.5080@AURM106297.americas.ad.flextronics.com> When I was a child we lived in Ashland, Kentucky for two years. We had cable television service. Ashland itself had only a PBS station. It was difficult to pull in stations from West Virginia. We had ABC, CBS, and NBC from Charleston, WV, the local PBS station, and an indepdendent station from Cincinnati known then as "Metromedia 19". We had no cable box. The stations were mapped to the VHF dial. Even though I was only in third grade I noticed a flicker as I turned the knob between channels 6 and 7. I discovered if I turned the knob just right so it was between those two channels we could get HBO. I seem to recall also some sort of information type channel. So of the 12 VHF channels (2 through 13) we had only 6: ABC, CBS, NBC, PBS, independent, and the information channel. John -- John Mayson <john@mayson.us> Austin, Texas, USA Date: Thu, 11 Nov 2010 11:37:07 -0600 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: early CATV, was: Bell System Technical Journal, 1922-1983 Message-ID: <tp6dnWeIWIJetEHRnZ2dnUVZ_qKdnZ2d@posted.nuvoxcommunications> In article <de342572-c8ec-4a42-b03b-41de3fac6ba4@v19g2000yqa.googlegroups.com>, Neal McLain <nmclain@annsgarden.com> wrote: >On Nov 9, 6:48 pm, danny burstein <dan...@panix.com> wrote: >> In <4CD8E573.6060...@annsgarden.com> Neal McLain <nmcl...@annsgarden.com> >writes: >> >> >Now here's my trivia question: how many channels did the first cable TV >> >system carry? >> >> The first "cable tv system", or the first "community antenna tv system"? >> And are you referring to the US, or including the rest of the world? >> >> -- >> _____________________________________________________ >> Knowledge may be power, but communications is the key >> dan...@panix.com >> [to foil spammers, my address has been double rot-13 encoded] > > >The first cable TV systems were community antenna tv systems. For >the first 25 years of the industry's existence, broadcast >retransmission (especially distant stations) was about the only thing >they had to sell. Many systems originated local programming ("local >origination") and carried PEG (public, educational, and government) >access programming, but these services didn't sell many subscriptions. > >The term CATV originally stood for community antenna TV. Somewhere >around the mid-70s, when CATV companies began carrying satellite- >delivered non-broadcast programming, the term CATV morphed into cable >TV. > >So the question refers to the first CATV system. > >As for your second question, I was thinking of the US, but the Taking the question exactly "as asked", the answser is "one". closed-circuit system, no external antennae of any sort. Date: Thu, 11 Nov 2010 10:30:07 -0600 (CST) From: jsw <jsw@ivgate.omahug.org> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Early cable TV competition (was Re: early CATV (was: BSTJ ...)) Message-ID: <201011111630.oABGU7SK018348@ivgate.omahug.org> >The term CATV originally stood for community antenna TV. Somewhere >around the mid-70s, when CATV companies began carrying satellite- >delivered non-broadcast programming, the term CATV morphed into cable >TV. The thing I remember most about early cable TV was a surprise I got when I was visiting some friends in Allentown in May of 1970. I was surprised to learn that they had not one but TWO local cable providers from which to choose, and that they had recently signed up with one. This was in the days when Sterling-Manhattan was struggling to get their initial NYC cable system launched in spite of all kinds of political and technical issues. The idea of competing cable systems in the NYC market was something not even dreamed of. ;-) My impression was that the Allentown system was more than just 'community antenna' TV, although I don't remember anything more than local, NYC, and Philly broadcast stations being on it. It did use a decoder box, but I don't remember much about it other than a rotary channel selector knob. For those who don't know the geography, I might describe the location of Allentown as being in the fair-to-almost-good range for Philadelphia broadcast stations and the crummy-to-fair rance of the NYC stations. Prior to cable, my friends had a fairly large rooftop antenna with a motor-driven rotor to swing it in the direction of either NYC or Philly. Date: Wed, 10 Nov 2010 19:29:08 -0500 From: Eric Tappert <e.tappert.spamnot@worldnet.att.net> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Bell System Technical Journal, 1922-1983 Message-ID: <vndmd6dc6pb20hf3df1q6c978910qe10il@4ax.com> On Tue, 09 Nov 2010 21:16:35 -0800, Richard <rng@richbonnie.com> wrote: >>***** Moderator's Note ***** >> >>Yes, we've seen this before, but I couldn't resist the chance to play >>"Ultimate Telecom Trivia"! >> >>Here's the question: why does a T1 line have 24 channels? >> >>Bill Horne >>Moderator > >First, they used a multiple of 12 channels, because it had to >interface with analog channel banks and the analog equipment used >multiples of 12 channels, called a "channel group." > >Second, they could reliably transmit and decode 24 channels between >manholes, but not 36 (too many errors due to transmission distortion). > >Another point of trivia: At one time, they had digital switching of >analog carrier channels: Transmission between cities was analog, but >the switches were digital. > >Dick > >***** Moderator's Note ***** > >Although T-Carrier banks had to interface with Analog banks, the >connections were always at "baseband", i.e., 300-4,000Hz connections >on pair wire. The Analog banks could never interoperate with T-Carrier >banks on the "high speed" side of the banks: a "T-1" 1.544 Mbps >circuit can't feed an analog carrier system. Apples and Oranges, >really. > > >Bill Horne >Moderator Bill, Generally true, but #4ESS had a frame called the "L to T connector" that actually took analog group signals and interfaced them directly to the digital switch fabric without intevening voice band connections. The interesting technical part of it was the use of digital signal processors (DSP1, actually, manufactured by Western Electric in Allentown PA) instead of analog signal processing. This was the first use of DSPs in the Bell System's network. BTW, are you looking for the N carrier connection?? N carrier was the dominant form of short haul carrier and the version in use in the early '60s put 24 voice channels on a four wire cable circuit. T carrier was intended for the same short haul market of interexchange and toll connecting trunks. As I recall, long haul trunks were administered at the group level, so a multiple of 12 was desirable. ET --- news://freenews.netfront.net/ - complaints: news@netfront.net --- Date: Wed, 10 Nov 2010 19:38:29 -0500 From: Eric Tappert <e.tappert.spamnot@worldnet.att.net> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: early CATV, was: Bell System Technical Journal, 1922-1983 Message-ID: <bgemd61bvbcs483d16amvufdppomeht2mu@4ax.com> On Wed, 10 Nov 2010 00:48:09 +0000 (UTC), danny burstein <dannyb@panix.com> wrote: >In <4CD8E573.6060408@annsgarden.com> Neal McLain <nmclain@annsgarden.com> writes: > >>Now here's my trivia question: how many channels did the first cable TV >>system carry? > >The first "cable tv system", or the first "community antenna tv system"? >And are you referring to the US, or including the rest of the world? Service Electric Cable TV Co. was started in June 1948 in Mahony City, PA with the three Philadelphia channels (3, 6, and 10). Reference: http://www.sectv.com/LV/our_founder.html Of course, this is for the US and doesn't count any Bell Labs' experiments or trials.... ET PS - the founder and his wife owned an appliance business and started the cable company so they could sell TV sets. --- news://freenews.netfront.net/ - complaints: news@netfront.net --- Date: Wed, 10 Nov 2010 23:09:06 -0500 From: tlvp <tPlOvUpBErLeLsEs@hotmail.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Happy anniversary cellphone! Message-ID: <op.vlzm5gh2itl47o@acer250.gateway.2wire.net> On Tue, 09 Nov 2010 07:08:08 -0500, T <kd1s.nospam@cox.nospam.net> wrote: > ... Friend of mine got 401-APE-COCK. Are you sure, sure, sure? It wasn't the Berkeley Systems folks' favorite dark beer, BSD Bock? Cheers, or bottoms up, -- tlvp -- Avant de repondre, jeter la poubelle, SVP ***** Moderator's Note ***** Oh, look, guys! Pandora left a box behind! Bill Horne Moderator Date: Thu, 11 Nov 2010 10:04:05 -0600 From: John Mayson <john@mayson.us> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Happy anniversary cellphone! Message-ID: <AANLkTinWt_v0=k06nW17Kw+RY3aqghCU9MeP-e-Nfp_n@mail.gmail.com> I have long been cursed with phone numbers laden with 0's and 1's so mine usually spell nothing. However I just returned from working overseas and just now figured my mobile phone number was +60-1-PIMP-HATS. -- John Mayson <john@mayson.us> Austin, Texas, USA Date: Wed, 10 Nov 2010 15:45:13 -0500 From: Fred Goldstein <fgoldstein.SeeSigSpambait@wn2.wn.net> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Why is T-1 24 Channels? Message-ID: <20101110204600.003E75456@mailout.easydns.com> Bill Horne wrote: > Yes, we've seen this before, but I couldn't resist the > chance to play "Ultimate Telecom Trivia"! Here's the > question: why does a T1 line have 24 channels? Bill, Neal's answer sounds right to me too, modulo slight editing . >Neal McLain <nmclain@annsgarden.com> wrote, >Because: > >- Each voice channel requires 4000 Hz bandwidth. Modulo guard band space, yes; it wsa basically 300-3400 Hz. Analog carrier systems of the day used SSB on frequency division multiplex. 60 kHz carried 12 channels = 1 Group; 5 Groups = a Supergroup. Note the 12. >- Harry Nyquist tells us that the sampling rate must be twice the >highest frequency within that bandwidth, or 8000 Hz. > >http://mathworld.wolfram.com/NyquistFrequency.html > >- The circuit uses Pulse Code Modulation with a sampling rate of 128 >steps, so 7 bits (plus one check bit) must be transmitted for each sample. Indeed; the D1 channel bank was 7-bit PCM, vs. 8 bit later; the "robbed" bit is for signaling, not parity. >- Manholes in urban areas are about 6000 feet apart, which is the >distance between loading coils in a voice loop. > >- Data repeaters have to be accessible for service (i.e., in manholes), >so they must be 6000 feet apart. Manholes are much closer together than that, as needed for pulling and access. LOADING COILS are 6000 feet apart, and used in rural areas, and were used on voice-frequency trunks. T1 was designed as a metropolitan area trunk system, for links between COs less than 50 miles apart. Those were often loaded wire, so they designed it to put repeaters in loading coil cases, at the same spacing. >- The circuit must operate over No. 22 twisted pair. > >- Research at Bell Labs in the 1960s showed that the maximum data rate >that could be reliably transmitted over a distance of 6000 feet over No. >22 conductors is about l.6 Mb/sec. Presumably, this research included >allowances for overspaced manholes, wet cable, corroded splices, ambient >temperature variations, and anything else that Murphy could dream up. > >- Maximum permissible number of channels = > >(1600000 bits/second) / (8000 samples/second/channel) / (8 bits/sample) >= 25 channels. > >- Subtract one channel for overhead (framing and signaling) yields 24 >channels. It would be (as Eric Tappert noted) rounded to a multiple of 12 channels, since that was the Group size of the analog carrier systems that it was replacing. A T1 carried as many voice channels as a digroup. Date: Thu, 11 Nov 2010 15:21:52 -0500 From: Monty Solomon <monty@roscom.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Users as Toast: The Blocking of Google TV Message-ID: <p062408e9c901ff1b6c3b@[10.0.1.3]> Users as Toast: The Blocking of Google TV Lauren Weinstein October 22, 2010 Greetings. The day started badly. All he wanted was a piece of toast. Yet instead of creating a crispy slice of goodness, his General Electric toaster ejected the still soft slice, and flashed a bizarre admonition on its display (odd, he didn't even remember it having a display) -- informing him that due to an ongoing dispute with Van de Kamp's bakeries, he was blocked from toasting that particular brand of bread until further notice. How droll. At least he could head out and pick up something to eat elsewhere. But he was low on gas -- better buy some first. More trouble. The pump refused to operate. What's this flashing on its screen? A list of acceptable car brands that have made deals with ARCO. His old car wasn't on the OK list. So -- no gas. Amazing. What's the world coming to? Back home, at least he can watch some TV. Now what? Instead of shows, messages are popping up hot and heavy. CBS says they will only allow viewers using SONY televisions to tune in. FOX demands Toshiba or Samsung. The DuMont network insists that you use a Farnsworth set. DuMont? Farnsworth? What the blazes is happening today? Somebody help! HELP! And he awoke in a cold sweat from the nightmare. Phew. Just a bad dream. Better calm down and watch the new Google TV -- go relax with some Web shows on the big screen. He settled down in his easy chair to wind down -- and his face twisted into a maniacal grin as he discovered that Hulu and the major broadcast networks have blocked much Web viewing by Google TV users ( http://bit.ly/ddgNCY [PC World] ). Reaching for the heavy hammer on the table to his side, he slowly approached the array of electronic devices stacked before him ... There has been much speculation about motivations for the blocking of most full episode Web programming from Google TV users -- first by Hulu, then by the conventional broadcast networks. Some observers suspect that disparities in ad rates between broadcast and Web versions of programs are the primary cause. Others have suggested that it's payback to Google for refusing to censor search results to try "hide" sites that offer pirated programming. Google itself has offered a diplomatically worded statement noting that it's up to program suppliers to decide which users they're willing to service. Understandably, Google doesn't want to burn any bridges, especially before they've been fully built. But in my view, the purposely blocking of particular viewing platforms for other than legitimate technical reasons (e.g. genuine, serious display incompatibilities) is unacceptable -- and should be illegal. ... http://lauren.vortex.com/archive/000774.html Date: Thu, 11 Nov 2010 15:24:08 -0500 From: Monty Solomon <monty@roscom.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Update: How They're Blocking Google TV (with Screenshots) Message-ID: <p062408eac901ff357265@[10.0.1.3]> Update: How They're Blocking Google TV (with Screenshots) Lauren Weinstein November 06, 2010 Greetings. In Users as Toast: The Blocking of Google TV, I strongly criticized the blocking of the new Google TV (GTV) products by a range of network TV Internet services. In particular, I suggested that such selective blocking of specific hardware devices for other than legitimate technical reasons was not only inappropriate, but also should likely be considered illegal. The inanity of this situation is further enhanced by the fact that users can display fullscreen images from these online networks directly from PCs equipped with HDMI ports (or via inexpensive DVI to HDMI adapters). So obviously the real issue "in play" isn't the simple blocking of large screen video displays per se. A number of persons have asked me for more detailed information about how Google TV blocking is actually occurring. Let's look at a couple of preliminary examples today (many thanks to Google for providing me with a Google TV unit for these explorations and experiments). Links below point to associated screenshots and photos. For all of these cases, a conventional Windows 7 PC and a Google TV box (Logitech Revue) -- both running a Chrome browser -- were connected to the same Ethernet switch, and accessed the Internet via the same NAT'd address during the test periods. In practice, blocking of GTV is occurring at two different levels. ... http://lauren.vortex.com/archive/000777.html Date: Thu, 11 Nov 2010 10:52:33 -0800 From: Richard <rng@richbonnie.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Bell System Technical Journal, 1922-1983 Message-ID: <k3eod6pqjslu5kludu8u5dlf6i25gle9jv@4ax.com> On Tue, 09 Nov 2010 21:16:35 -0800, Richard <rng@richbonnie.com> wrote: >>***** Moderator's Note ***** >> >>Yes, we've seen this before, but I couldn't resist the chance to play >>"Ultimate Telecom Trivia"! >> >>Here's the question: why does a T1 line have 24 channels? >> >>Bill Horne >>Moderator > >First, they used a multiple of 12 channels, because it had to >interface with analog channel banks and the analog equipment used >multiples of 12 channels, called a "channel group." > >Second, they could reliably transmit and decode 24 channels between >manholes, but not 36 (too many errors due to transmission distortion). > >Another point of trivia: At one time, they had digital switching of >analog carrier channels: Transmission between cities was analog, but >the switches were digital. > >Dick > >***** Moderator's Note ***** > >Although T-Carrier banks had to interface with Analog banks, the >connections were always at "baseband", i.e., 300-4,000Hz connections >on pair wire. The Analog banks could never interoperate with T-Carrier >banks on the "high speed" side of the banks: a "T-1" 1.544 Mbps >circuit can't feed an analog carrier system. Apples and Oranges, >really. > > >Bill Horne >Moderator In the book "Transmission Systems For Communications", Bell Telephone Laboratories, Inc., Fifth Edition, 1982, Page 596: "FDM·to·TDM Connector. Long-haul transmission tends to be dominated by analog FDM (frequency-division multiplex) systems (primarily line-of-sight radio relay). On the other hand, digital switching of long­distance telephone traffic is rapidly being introduced. Thus, it is necessary to have an economical interface between FDM transmission and digital switching. The most convenient place in the hierarchy to perform this function is at the group level. In its simplest conceptual form (LT-1), this FDM-to-TDM connector consists functionally of two A-type channel banks (see Chap. 15) which demodulate two FDM groups into 24 individual voice channels and a digital channel bank which encodes these channels into DS1 format. As A/D conversion and digital processing become cheaper, however, it will become economical to implement the FDM group to TDM converter by performing an A/D conversion directly on the group signals and then translating the encoded FDM signal directly into DS1 format (see Fig. 27-2) by digital processing techniques. This eliminates many of the more expensive analog filters and modulation equipment (see Chap. 35)." Dick Date: Thu, 11 Nov 2010 13:18:58 -0800 (PST) From: Cecile <cecile.farmer@gmail.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: T-Mobile 4G commercials Message-ID: <7b4492f7-fe01-4a5b-9335-ac39b7f8ac40@n24g2000prj.googlegroups.com> On Nov 5, 10:46 am, "Adam H. Kerman" <a...@chinet.com> wrote: > T-Mobile is advertising 4G. Are they reselling Sprint and Clear, or did > they actually erect a network of their own? T-mobile's network is HSPA+. Not WiMAX nor LTE. For 4G you'll want to head to www.clear.com! Cecile at CLEAR :) ***** Moderator's Note ***** I don't usually allow posts that endorse a specific product, but this one meats my exception criteria: 1. It's informative. 2. It's clear that it's a CLEAR employee plugging the product. Bill Horne Moderator 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 Bill Horne. 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 moderated by Bill Horne. 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. 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