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The Telecom Digest for July 09, 2011
Volume 30 : Issue 169 : "text" Format
Messages in this Issue:
Re: System Clock Apparently Gaining One Second Every 30 Minutes(John Meissen)
Metro PCS type Service in UK(1506)
Re: Metro PCS type Service in UK(John Levine)
Re: System Clock Apparently Gaining One Second Every 30 Minutes(Robert Bonomi)
Re: System Clock Apparently Gaining One Second Every 30 Minutes(Adam H. Kerman)
Re: System Clock Apparently Gaining One Second Every 30 Minutes(tlvp)
Re: "Underground" demarc?(Robert Bonomi)
Re: "Underground" demarc?(Doug McIntyre)
Re: "Underground" demarc?(Scott Dorsey)
Re: Battery power support today(Robert Bonomi)
Re: Battery power support today(Marc Haber)
Re: Battery power support today(David Clayton)

====== 29 years of TELECOM Digest -- Founded August 21, 1981 ======

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Date: Thu, 07 Jul 2011 15:47:23 -0700 From: "John Meissen" <john@meissen.org> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes Message-ID: <20110707224723.9C29217F605@john> In article <siegman-B5122E.07421007072011@bmedcfsc-srv02.tufts.ad.tufts.edu> AES <siegman@stanford.edu> wrote: > In article <slrnj1acpi.9at.gsm@cable.mendelson.com>, > "Geoffrey S. Mendelson" <gsm@mendelson.com> wrote: > > There may have been a telephone based service where you got clock pulses > > from the atomic clock (I think there is only one in the country that is > > available to civilians), but those days are long gone. > > > > Just for the record, a few days ago I found in a drawer one of those > Oregon Scientific battery-powered weather gadgets with a couple of > remote temperature gauges. Changed the batteries, set it on a shelf in > my office, within a day or so it had accurately self-synched it's date > and time to somebody's broadcasts out of the ether . (Except it won't > and I can't push its Year beyond 2004; it had been in that drawer for a > while.) Probably just monitors WWV's transmission: http://www.nist.gov/pml/div688/grp40/wwv.cfm I've slowly been replacing all of the clocks in my house with ones that set themselves. It was interesting to see which ones failed when they changed the DST dates because they had hard-coded them. There's no reason to hard-code it because the DST status is part of the data stream. ***** Moderator's Note ***** Please tell us which ones were able to handle the DST change. Bill Horne Moderator
Date: Thu, 7 Jul 2011 07:37:20 -0700 (PDT) From: 1506 <e27002@gmail.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Metro PCS type Service in UK Message-ID: <a38de0a0-56cf-464e-9ed2-8228bcfe2f31@m18g2000vbl.googlegroups.com> Does anyone know of a UK eqivalent of the US Metro PCS cellphone service? Metro PCS offer unlimited use for a monthly flat fee, USD40.00 [in the] US, and USD50.00 International. Thanks
Date: 8 Jul 2011 15:52:13 -0000 From: "John Levine" <johnl@iecc.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Metro PCS type Service in UK Message-ID: <20110708155213.40272.qmail@joyce.lan> >Does anyone know of a UK eqivalent of the US Metro PCS cellphone >service? Metro PCS offer unlimited use for a monthly flat fee, >USD40.00 [in the] US, and USD50.00 International. US carriers tend to have lower cost high volume plans than UK carriers. Also, there's no UK carrier with coverage as limited and spotty as Metro PCS so it's hard to make a direct comparison. O2 offers unlimited talk and text for 46.00 month to month, 41.00 on a 12 month contract if you bring your own phone. Most carriers offer unlimited texts or unlimited calls to landlines as an option in their 20 and up plans. Note that the UK prices are the real prices, while the US prices invariably also charge a variety of taxes and fake surcharges. R's, John
Date: Thu, 07 Jul 2011 19:26:19 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes Message-ID: <kqCdnfjrbeU204vTnZ2dnUVZ_hKdnZ2d@posted.nuvoxcommunications> In article <slrnj1acpi.9at.gsm@cable.mendelson.com>, "Geoffrey S. Mendelson" <gsm@mendelson.com> wrote: > > There may have been a telephone based service where you got clock pulses > from the atomic clock (I think there is only one in the country that is > available to civilians), but those days are long gone. There were, and are, _at_least_two_. One from NIST, with a Colorado number, in the Boulder area, IIRC. A second from the U.S. Naval Observatory, in Virginia, as I recall, but it is an area-code 202 number. There may be modem access to WWVH, I'm not sure -- there is telephone access to the =voice= time there, in addition to the WWV voice channel in Colorado. The NIST facility is amazingly accurate. They have 'smarts' on the server end that measure the round-trip latency to the user, and advance the 'tick' so that it arrives at the user's location at the proper instant. With quality software, one can set the system clock with sub- millisecond accuracy. If memory serves, the 'jitter' is around 15 _micro- second_.
Date: Fri, 8 Jul 2011 05:34:16 +0000 (UTC) From: "Adam H. Kerman" <ahk@chinet.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes Message-ID: <iv64so$pho$5@news.albasani.net> AES <siegman@stanford.edu> wrote: >Just for the record, a few days ago I found in a drawer one of those >Oregon Scientific battery-powered weather gadgets with a couple of >remote temperature gauges. Changed the batteries, set it on a shelf in >my office, within a day or so it had accurately self-synched it's date >and time to somebody's broadcasts out of the ether . (Except it won't >and I can't push its Year beyond 2004; it had been in that drawer for a >while.) Same pattern as 1994 on the perpetual calendar.
Date: Thu, 07 Jul 2011 18:30:33 -0400 From: tlvp <tPlOvUpBErLeLsEs@hotmail.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: System Clock Apparently Gaining One Second Every 30 Minutes Message-ID: <op.vx9ss7w4itl47o@acer250.gateway.2wire.net> On Thu, 07 Jul 2011 10:42:10 -0400, AES <siegman@stanford.edu> wrote: > Re mysterious computer time glitches, and the NERC 60 Hz story: > > In article <slrnj1acpi.9at.gsm@cable.mendelson.com>, > "Geoffrey S. Mendelson" <gsm@mendelson.com> wrote: > >> There may have been a telephone based service where you got clock pulses >> from the atomic clock (I think there is only one in the country that is >> available to civilians), but those days are long gone. >> > > Just for the record, a few days ago I found in a drawer one of those > Oregon Scientific battery-powered weather gadgets with a couple of > remote temperature gauges. Changed the batteries, set it on a shelf in > my office, within a day or so it had accurately self-synched it's date > and time to somebody's broadcasts out of the ether . (Except it won't > and I can't push its Year beyond 2004; it had been in that drawer for a > while.) Following the example of the y2k shenanigans I had to invent to retain the usefulness of an AT&T-branded "Computer telephone 8130" (nominated 'Computer Telephony Product of the Year' the year it came out late last century), you can get month, day, and date to come out just fine if you adjust the year to exactly 28 years ago -- not 2011 (which it won't do, you report), but 1983. (Or won't it accept 1983, either? The old 8130 happily accepted 1972 in 2000.) HTH. And cheers, -- tlvp (who's still wondering how that 8130 could have been Product of the Year one year, and a sacrificial y2k victim a few years later, as AT&T had no firmware update prepared for it.) -- Avant de repondre, jeter la poubelle, SVP
Date: Thu, 07 Jul 2011 18:18:04 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: "Underground" demarc? Message-ID: <gKqdnd8VTocxo4vTnZ2dnUVZ_rmdnZ2d@posted.nuvoxcommunications> In article <hge917l55a2cni5ms0etmuoq8k7e2bi7ol@4ax.com>, T. Keating <tkusenet@ktcnslt.com> wrote: >On Fri, 1 Jul 2011 10:59:42 -0700 (PDT), grumpy44134 ><grumpy44134@gmail.com> wrote: > >>My friend is having an intermittent problem with her home phone. I >>told her to find the gray demarc/Telephone Network Interface (Ohio) >>box. After not being able to find it, she reminded me her power and >>telephone wires were underground to her house. Question - where is >>the demarc for underground telephone service (in Ohio)? > >Look for the electric service meter and power main disconnect. > >The teleco demarc should be close to it, (for grounding/bonding >purposes). snicker Where I grew up, they were on *opposite*sides* of the house. Not to mention that the power came in overhead, and the phone was underground.
Date: 07 Jul 2011 15:27:20 GMT From: Doug McIntyre <merlyn@geeks.org> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: "Underground" demarc? Message-ID: <4e15d058$0$79797$8046368a@newsreader.iphouse.net> Lisa or Jeff <hancock4@bbs.cpcn.com> writes: >On Jul 6, 11:10am, klu...@panix.com (Scott Dorsey) wrote: >> >In my (limited) experience, even if there's no official demarc, >> >there's invariably a lightning protection block, with four or more >> >screw terminals, cylindrical fuses, and a ground wire. >> >> That block is, for all legal purposes, the demarc. You own the wiring >> after it, they own the wiring before it. >Ok, but how does it work if above "block" handles a group of dwelling >units (as does the unit where I live)? I don't think it would be a >good idea for individuals to be fooling around in a junction box that >serves multiple customers. Its totally up to the building owner how they deal with it. In most of the bigger apartment buildings I've done work in, the telco will be in (usually, sometimes forgotten to be) locked closets along with the cable TV plant. Sometimes with some pretty beefy locks (ie. Medeco, that I had to leave behind my drivers license to get the key from the building people). Smaller/older buildings may just have it somewhere in the basement, or an outside NI box hanging out somewhere, maybe locked, probably not. Its more of a matter of people don't usually mess with it because they have no idea what they are looking at other than a bunch of wires behind a door/inside a can/behind that panel, not even realizing they could do a bunch of messing up people by messing with all the wires. Plus the ones that could really mess with it and have punch down tools, test sets, etc. could do the same sort of problem from many places, not just one specific NI box somewhere.
Date: 7 Jul 2011 10:12:57 -0400 From: kludge@panix.com (Scott Dorsey) To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: "Underground" demarc? Message-ID: <iv4et9$e4p$1@panix2.panix.com> Lisa or Jeff <hancock4@bbs.cpcn.com> wrote: >On Jul 6, 11:10am, klu...@panix.com (Scott Dorsey) wrote: > >> >In my (limited) experience, even if there's no official demarc, >> >there's invariably a lightning protection block, with four or more >> >screw terminals, cylindrical fuses, and a ground wire. >> >> That block is, for all legal purposes, the demarc. You own the wiring >> after it, they own the wiring before it. > >Ok, but how does it work if above "block" handles a group of dwelling >units (as does the unit where I live)? I don't think it would be a >good idea for individuals to be fooling around in a junction box that >serves multiple customers. That's how it works. And no, it's maybe not a good idea for individuals to be fooling around in there, especially since that box may contain multiplied pairs from other buildings as well. But that's how it works. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis."
Date: Thu, 07 Jul 2011 19:08:38 -0500 From: bonomi@host122.r-bonomi.com (Robert Bonomi) To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Battery power support today Message-ID: <T9ydnWbB8t0b14vTnZ2dnUVZ_q2dnZ2d@posted.nuvoxcommunications> In article <iv4gkb$6u8$1@dont-email.me>, Dave Garland <dave.garland@wizinfo.com> wrote: >On 7/6/2011 3:49 PM, Robert Bonomi wrote: > >> Electric blankets are a non-issue, even relatively speaking. They are >> relatively low-power devices (i.e. around 150 watts) to start with, and >> that power is split across something like 20 or 30 separate wires running >> the length of the blanket. So you're looking at maybe 5-10 watts from >> each wire in the blanket, assuming it's all the way on. > >All the electric blankets I've seen had a single wire per control >unit, that ran in a serpentine fashion lengthwise. So the current is >the same everywhere (about 800 ma, if the blanket or side is 100W). And if there are 20 passes in the serpentine path, how many watts is each pass putting out? :) BTW, TTBOMK, all remotely 'recently manufactured' electric blankets employ a step-down transformer, so that the voltage in the blanket is not at lethal levels, if there were to be an insulation failure 'near' the hot feed. >I believe that field strength will be related to current, rather than >wattage. Current and wattage differ only by a multiplicative constant (voltage) Field strength is related to both voltage and current. Otherwise transformers wouldn't work. That said, "watts is watts", for field strength -- what goes in a transformer at one voltage/current is what comes out at a different voltage/current, subject to internal losses, of course. *GRIN* > The traditional controller (don't know about modern ones, >but the one on my elderly electric blanket) is an on-off device that >varies heat by varying duty cycle, a clever design from the days >before semiconductors. Yup, that's one of the standard 'classical' controllers. The other uses an actual _thermostat_, with a remote bulb in the blanket, to sense/control actual temperature. >At a typical >> mid-range (or lower) setting for 'on all night' use, it's more like 2 watts >> per wire. Despite the relatively close proximity, This pales into >> insignificance relative to the 1500 watts powering a toaster, or the 5 >> kilowatts or so feeding an electric stove. >> > >The blanket's conductors are very close to you, though, less than a >half inch at closest approach. Agreed And a _thousand-to-one_ differential in in total power, concentrated into a *much*smaller* area (how many 'pieces of bread' does it take to cover an electric blanker?) means toaster field-strength is many orders of magnitude higher. > And the exposure time (4 hr/day >assuming a 50% duty cycle and 8 hours in bed) is much longer than a >toaster (a few minutes/day). Once past a relatively short initial interval, effects are -not- cumulative with regard to time of exposure. There is an 'equilibrium point' reached. where the effects are radiated off as fast as they are absorbed. >I'd guess a toaster would also have a lot of field cancellation, since >the heating elements run back and forth. The -same- cancellation effect applies to high-voltage transmission lines. If the "power line risks" people are free to disregard that in their scare propaganda, I am free to use the same 'logic' in the 'close range' case. Remember, I prefixed the original remarks with a qualifier about 'those who worry about those things...'. Using their rationale, the examples I drew are "comparable". *GRIN*
Date: Thu, 07 Jul 2011 17:52:27 +0200 From: Marc Haber <mh+usenetspam1118@zugschl.us> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Battery power support today Message-ID: <iv4knr$1qr$1@news1.tnib.de> Lisa or Jeff <hancock4@bbs.cpcn.com> wrote: >I believe such locomotives generate AC, rectifier to DC, then convert >it back to AC for traction usage; apparently the frequency is varied >to drive the motor. (There are others who can explain modern AC >traction better than I can). What confuses me is why bother to >convert to DC and back to AC instead of merely generating at AC and >using that? The traction motors need AC of frequency and tension that fits the current situation, which usually does not fit the current that the gensets put out. So, semiconductors are used to "make" the current that the motors want to see. That is easier if the input is DC, hence the DC link between genset and traction converter. Greetings Marc -- -------------------------------------- !! No courtesy copies, please !! ----- Marc Haber | " Questions are the | Mailadresse im Header Mannheim, Germany | Beginning of Wisdom " | http://www.zugschlus.de/ Nordisch by Nature | Lt. Worf, TNG "Rightful Heir" | Fon: *49 621 72739834
Date: Thu, 07 Jul 2011 23:27:41 +1000 From: David Clayton <dcstarbox-usenet@yahoo.com.au> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Battery power support today Message-ID: <pan.2011.07.07.13.27.35.64827@yahoo.com.au> On Wed, 06 Jul 2011 15:15:33 -0700, Lisa or Jeff wrote: > On Jul 5, 8:53 pm, Wes Leatherock <wleat...@yahoo.com> wrote: > >> Many of the newer locomotives are built with alternators.  It's a >> growing trend.  DC is better in some cases, but AC in others, > >> ***** Moderator's Note ***** >> Another preconceived notion destroyed! If a man can't make up the >> truth, what's the world going to come to?! > > Historically, diesel-electric railroad locomotives used DC motors for > traction. But new electronic control technology allows the use of AC > motors which apparently offer superior low speed service, such as moving > a heavy train up a mountain. I understand there are other advantages to > AC motors (fewer wearing parts?) but I'm not sure what they are. > I certainly know that switching and controlling HV AC is a lot simpler than DC - perhaps the outstanding efficiency of switch mode power technologies as overcome the earlier limitations of AC? > I believe such locomotives generate AC, rectifier to DC, then convert it > back to AC for traction usage; apparently the frequency is varied to > drive the motor. (There are others who can explain modern AC traction > better than I can). What confuses me is why bother to convert to DC and > back to AC instead of merely generating at AC and using that? In my city the metro train system uses a legacy 1500V DC supply, and some of the rolling stock delivered over the last decade seem to convert this to AC for their traction motors. These newer trains are basically imported from overseas with modifications instead of constructed especially for the incumbent infrastructure, as the older ones were made until relatively recently, and seem to be "native" AC trains with mods to run on a DC network. At a terminus you can hear a motor spin up in preparation about a minute before departure, which to me sounds like a DC motor cranking up to drive an AC generator - I never used to hear that on the old pure DC trains. And to keep the post (slightly) telecoms related, the trains used to have their own radio comms network, which was then replaced by GSM which is now (apparently) being replaced by another digital radio network because the GSM network had too many black spots at the extremities. -- 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.
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