On 10/1/2006 at 3:13 PM Jim at work wrote: Well, Salem is 503 also. But 541 could be anywhere from the Pacific Ocean, over a couple of mountain ranges and river valleys to the eastern desert.. Cheers, Chuck (in 541, but that's not saying much)

On 10/1/2006 at 7:44 PM Sridhar Ayengar wrote: Yes, but it doesn't cover any new territory. 971 is basically a "new number" overlay code for the 503 area. I wish the telco powers that be would have thought of that scheme when 541 was broken out of the 503 (used to be the entire state) back in the 90's. It would have saved a bunch of printing and mailing costs. Salem (seat of the state government) northwards to the Portland Metro area were the only places to hang onto 503. For a long time, a store in Montreal was getting a bunch of our calls because many PBX's wouldn't handle area codes that didn't have 1 or 0 as the middle digit. So, folks just figured that 541 was an error and that the correct code had to be 514. It's very strange to think of "area codes" in terms of today's technology. I'd have expected that the telcos would have long since assigned everyone their own personal non-area-coded 11 digit universal telephone number. Heck, add a check digit and make it 12 digits, like a credit card. Maybe I'll live long enough to see telephone numbers without country and area codes--but I'm not holding my breath. Cheers, Chuck

On 10/1/2006 at 11:38 PM der Mouse wrote: I know it's OT, but I see the local cable company offering phone service and I've got Skype on my machine. Doesn't the POTS model seem more than a little dated? Cheers, Chuck

On 10/2/2006 at 11:17 AM der Mouse wrote: That's why I said "POTS model" :) There's a "Temple of Qwest" consisting of several very large boxes erected a couple of years ago on a concrete pad that's located at a corner of my property here. It services heaven only knows how many thousand pairs--in my case, "the last mile" is only about 400 ft. I get great DSL, yet the CO is somewhere around 7 wire miles away--so I've got a pretty good idea of what's inside the temple. No, my comment referred to the mechanism used to address individual subscribers and the quaint hierarchy of country, area and local exchange prefixes. "Long long time" is relative. I recall that sections of Sunnyvale (in the middle of Silicon Valley) north of El Camino were serviced by a type 2 crossbar switch well into the 80's. For me, that's recent history. I still have the location of an old coaxial toll line marked by warning signs nailed to old tree stumps for the "Pacific Telephone and Telegraph Company" that crosses my property. Near the property line, there's an access point where you can clearly see a pair of coaxial lines tie into a terminal block. And the coax replaced an even older surface line--I can still find glass insulators and bits of iron pole hardware in the soil aong the route. Cheers, Chuck

It was thus said that the Great der Mouse once stated: But what about cell phones and roaming? Last year I went to Las Vegas with a friend of mine. My cell phone is in the 561 area code (Palm Beach County), my friend's phone is in the 205 area code (Tuscaloosa, Alabama). Las Vegas is 702. My Dad was able to call me (760) while I was in Las Vegas, and I was able to call my friend (205 area code, although phyically five feet away) from my cell phone. How do they handle *that*? -spc (Given the horror stories I've heard about phone switch technology, I'm amazed it all even works ... )

On Mon, 2 Oct 2006, Sean Conner wrote: This is getting dangerously OT, but what the hell, I used to test these things :-) All calls from the PSTN to a particular cell number go to that number's 'home' switch. This switch owns the enclosing block of numbers in the PSTN sense. It also keeps track of which switch is the 'serving' switch for a particular subscriber at any time. When your phone moves into a new location area, it preforms a location updating procedure; this procedure places the phone into the serving switch's list of visitors, the serving switch then lets the home switch know the current serving switch's address, and the home switch tells the old serving switch to purge the number from it's list of visitors. When a call comes in for a cell subscriber, the PSTN routes it to the home switch based on the number alone; the home switch looks up the address of the serving switch for this subscriber in it's database and routes the call to the serving switch, which then delivers it to the phone. Calls from the cell phone are usually handled directly by the serving switch (i.e. they're sent into the PSTN and if the recipient is also a cell number the call delivery procedure above is used by the recipient's home switch). As a result, your mobile-to mobile call with both of you roaming can have either 2 to 4 legs (maybe more if forwarding is in use). It's 2 legs (you -> serving switch -> your buddy) if you're on the same serving switch and it can figure out that the call recipient is on the same switch as the sender. It's 4 legs (you -> your serving switch -PSTN-> your buddy's home switch -PSTN-> your buddy's serving switch -> your buddy) if you're not on the same serving switch or your serving switch doesn't have enough information to figure out that it's also your buddy's serving switch. More or less the same thing is done for number portability, except there can be 3 switches: the switch that owns the number in the PSTN sense, the switch that is the new 'home' and tracks the location of the phone, and the serving switch to which the phone is actually talking. The owns number switch to new home switch mapping is static (updated by people, not software) and the protocols used for number portability are not the same as those used for roaming, but the idea is basically the same. Now take that explanation, stir in tons of telco jargon, make it about 5 times more complicated due to various features (call forwarding, anyone?), route optimizations (saving money on trunk use is a big deal for carriers) and security procedures, and you'll get what's actually going on :-P Alexey

I suspect that this works only because most cellphones are not roaming at any given moment. (To those who know - can the cellphone system handle having more than a small fraction of the cellphones roaming?) I also note that this works only because each cellphone *has* a "home". Individual portable phone numbers might work if handled similarly, but it would make service for an individual's phone number dependent on a switch that the individual may not have any particular relation to at all (and, depending on how numbers are assigned, may never have had). If I lose service when the switch down the street is knocked out, I find that a lot more tolerable than if, say, I lose service whenever some switch off in Germany, which I've never lived near, dies. Of course, PSTN facilities are supposed to have five nines of uptime. Five minutes a year is probably livable, even if you square it (ten minutes a year) because two mostly unrelated hops (caller -> home switch -> current switch) are involved. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

It somewhat looks like this is happening quite well in our cellphone based society. Is the snail mail system different in any way? These concerns can be handled reasonably, even for the over-the-top privacy types. The cellphone guys are doing a pretty good job. There is still some hierarchy, but noweher near as there used to be. Most of Notes on the Network is obsolete (or getting there fast). -- Will