29 Years of the Digest ... founded August 21, 1981
The Telecom Digest for June 07, 2011
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Date: Mon, 06 Jun 2011 03:17:35 -0700 From: Sam Spade <email@example.com> To: firstname.lastname@example.org. Subject: Re: Busy trunks--subscriber behavior Message-ID: <jqadndXxw4LdNHHQnZ2dnUVZ_uCdnZ2d@giganews.com> Lisa or Jeff wrote: > On May 28, 10:32 pm, T <kd1s.nos...@cox.nospam.net> wrote: > >>In article <LfudnW3r6shd_VzQnZ2dnUVZ_gedn...@giganews.com>, >>s...@coldmail.com says... >> >> >>>If a lot of subscribers remained off-hook, no harm, no foul, unlike a No >>>5 XBAR, which could crash given sufficient permanent off-hooks. >> >>That's because the 5 XBAR used the markers for everything and being that >>markers were nothing but logical arragangements of relays, and limited >>depending on the office design, it was a fairly simple matter to >>overwhelm them. > > > I'm not an expert on switching, but I do not think the above is > correct. According to the Bell Labs history, the "marker" isn't > called in until all the digits have been registered in the > "originating register" and the "line link". So, I'm not sure the > marker can be overwhelmed by numerous off-hooks. > > I don't know if a crossbar switch could "crash" from being overwhelmed > with traffic--"crash" being the system fails to work at all and needs > external intervention to reset it (a "reboot"). Rather, I think call > requests, either subscribers or external trunks coming in, would > simply get slow service until traffic levels reduced. > > The Bell System recognized the need for network control fairly early > on and if too many calls were flooding a particular exchange or region > they would manually busy out the trunks so the region wouldn't get > overloaded. From panel onward switches contained numerous checks and > alarms would sound if there were problems. > > Also, both panel and crossbar had timers on off hook so that if the > subscriber didn't complete their dialing within a specified time, the > receiving equipment was cut off to avoid tying it up. > > Other BSTJ articles discussed what happens to subscribers if there are > too many off-hook (people trying to make calls) all at once. > Obviously this was something they had to provide for very early on as > emergency situations (eg major storms) would spark such calling. > Later, radio promotions and the like could do so. One issue was > whether a subscriber had "a place in line" while waiting, that is, > were they served in turn, or randomly picked when a receiver became > available. The BSTJ also gives rather complex statistical analysis > formulas on all of this (as well of course trunk group usage and > blocking). > I don't know the technical reasons but I do know that 65 permanent ROHs would crash a No. 5 XBAR. That was one of the reasons for 24/7 maintenance staff to pickel those ROHes, thus rendering them harmless.
Date: 5 Jun 2011 14:29:07 -0000 From: "John Levine" <email@example.com> To: firstname.lastname@example.org. Subject: Re: Caller Pays vs. Called Party Pays (was Re: DSL Reports: AT&T Caps Have Arrived) Message-ID: <email@example.com> >I would think caller pays would severly restrict the usefulness of a >cellphone. [Who] would pay to call their plumber, electrician or >whatever if they only list a cellnumber? This turns out to be one of those religious issues like toll alerting. People assume that whatever they're used to is a law of nature, and anything else is perverted and wrong. Everyone in Europe has a mobile phone, and on mobiles, calls to other mobiles tend to cost the same as calls to landlines, so people don't care. I happen to agree that mobile pays is overall better, since it puts competitive price pressure on both inbound and outbound prices, and allows number portability between landline and mobile, but people in caller-pays areas think it's swell that their inbound calls are "free". Also note that caller-pays areas invariably have separate number ranges for mobiles so there's no problem of knowing whether a call will be expensive. R's, John PS: If you're daunted by paying 50c to call the plumber, you're going to be really upset when you get his bill. ***** Moderator's Note ***** ... and the doctor said "Two Hundred Seventy dollars for an hour's work!!? I don't make that much, and I am a _surgeon_!!" The plumber shrugged his shoulders and replied "I know how you feel: I didn't make that much when I was a surgeon!" Bill Horne, who's father was a plumber Moderator
Date: Sun, 05 Jun 2011 08:53:36 -0400 From: "Pete Cresswell" <x@y.Invalid.telecom-digest.org> To: firstname.lastname@example.org. Subject: Re: Caller Pays vs. Called Party Pays (was Re: DSL Reports: AT&T Caps Have Arrived) Message-ID: <email@example.com> Per Wes Leatherock: >I would think caller pays would severly restrict the usefulness of a >cellphone. [Who] would pay to call their plumber, +1 on that. On one hand it would impede the conduct of business. OTOH, maybe Americans work too hard and basically cutting off their cell phones' incoming would give us a break. Also, there would seem tb the issue of callers not knowing what they are getting in to price-wise - unless there's something about cell phone numbers in Europe that makes them instantly identifiable. -- PeteCresswell
Date: Sun, 05 Jun 2011 14:25:09 +0100 From: Stephen <firstname.lastname@example.org> To: email@example.com. Subject: Re: Caller Pays vs. Called Party Pays (was Re: DSL Reports: AT&T Caps Have Arrived) Message-ID: <firstname.lastname@example.org> On Sat, 4 Jun 2011 17:39:21 -0700 (PDT), Wes Leatherock <email@example.com> wrote: > > >--- On Fri, 6/3/11, Joseph Singer <firstname.lastname@example.org> wrote: > >> Let's not get into the old saw of "their system is better than >> ours." In Europe and other countries where the subscriber doesn't >> pay to receive calls the calls are not free. The initiator of the >> call pays for all call charges and always at a non-negotiated rate. >> Whatever the tariff is that's what the caller pays and very often >> at a rate that's even higher than an international call to a >> regular number. Most people in North America get calling plans that >> give them a surfeit of available minutes or get a plan that gives >> them enough minutes that they can make just necessary calls. > >I would think caller pays would severly restrict the usefulness of a >cellphone. [Who] would pay to call their plumber, electrician or >whatever if they only list a cellnumber? there are tradeoffs. with caller pays countries tend to have reserved number ranges for types of call - eg in the UK all mobiles begin 07. - so you know what your cost of call is likely to be. - it make free call, geographic independent numbers and low cost call services more common here. The flip side is calls to a subscriber are paid for by the caller - so i dont get to pay to recieve a mobile call from some person in a call centre i dont want to talk to........ >I notice quite a few commercial vehicles now that list only a number >I recognize as a cell number. Most landline service in the U.S.A. is >flat rate, so there is no marginal cost for making a call to a land >line or to a cell number...in many cases the caller doesn't know >which he or she is calling. Plenty of fixed price / bundle minute deal here, initally mainly on mobiles. Bundles for landlines are normally limited to national fixed line + international calls. >And, as you note, most cell phone users have more minutes than they >use, so there is no marginal cost there, either. -- Regards email@example.com - replace xyz with ntl
Date: Mon, 06 Jun 2011 09:02:49 +1000 From: David Clayton <firstname.lastname@example.org> To: email@example.com. Subject: Re: Caller Pays vs. Called Party Pays (was Re: DSL Reports: AT&T Caps Have Arrived) Message-ID: <firstname.lastname@example.org> On Sat, 04 Jun 2011 17:39:21 -0700, Wes Leatherock wrote: > > --- On Fri, 6/3/11, Joseph Singer <email@example.com> wrote: > >> Let's not get into the old saw of "their system is better than ours." >> In Europe and other countries where the subscriber doesn't pay to >> receive calls the calls are not free. The initiator of the call pays >> for all call charges and always at a non-negotiated rate. Whatever the >> tariff is that's what the caller pays and very often at a rate that's >> even higher than an international call to a regular number. Most people >> in North America get calling plans that give them a surfeit of available >> minutes or get a plan that gives them enough minutes that they can make >> just necessary calls. > > I would think caller pays would severly restrict the usefulness of a > cellphone. [Who] would pay to call their plumber, electrician or whatever > if they only list a cellnumber? It seems to work quite well in Australia, there was initial resistance when people started doing this sort of thing but they have adapted. One big advantage of callers paying when calling tradesman is that they are more concise when they [are] paying the meter.... -- 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.
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.
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