Return-Path: Received: by massis.lcs.mit.edu (8.7.4/NSCS-1.0S) id IAA25481; Tue, 28 Oct 1997 08:29:05 -0500 (EST) Date: Tue, 28 Oct 1997 08:29:05 -0500 (EST) From: editor@telecom-digest.org Message-Id: <199710281329.IAA25481@massis.lcs.mit.edu> To: ptownson Subject: TELECOM Digest V17 #293 TELECOM Digest Tue, 28 Oct 97 08:29:00 EST Volume 17 : Issue 293 Inside This Issue: Editor: Patrick A. Townson Re: New York Times on Net Day (Thomas G. Spalthoff) Re: Signaling, Routing and General Confusion (Al Varney) Re: Tower Site Leases (John Driscoll) Re: Tower Site Leases (Marty Bose) NiCad Memory Effect (was: New Cellular Phone Experience) (Bob Keller) Re: InTRA-LATA Carrier Verification (Lee Winson) Re: InTRA-LATA Carrier Verification (Marty Tennant) Re: Is Southwestern Bell Allowed to do This? (Bruce Wilson) Re: Is Southwestern Bell Allowed to do This? (Louis Raphael) Re: Phone Problems in Nebraska? (Jason Forst) Re: Phone Problems in Nebraska? (Bruce Wilson) Re: Phone Problems in Nebraska? (Greg C. Ashley) TELECOM Digest is an electronic journal devoted mostly but not exclusively to telecommunications topics. It is circulated anywhere there is email, in addition to various telecom forums on a variety of public service systems and networks including Compuserve and America On Line. It is also gatewayed to Usenet where it appears as the moderated newsgroup 'comp.dcom.telecom'. Subscriptions are available to qualified organizations and individual readers. Write and tell us how you qualify: * telecom-request@telecom-digest.org * The Digest is edited, published and compilation-copyrighted by Patrick Townson of Skokie, Illinois USA. You can reach us by postal mail, fax or phone at: Post Office Box 4621 Skokie, IL USA 60076 Phone: 847-727-5427 Fax: 773-539-4630 ** Article submission address: editor@telecom-digest.org ** Our archives are available for your review/research. 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Spalthoff) Subject: Re: New York Times on Net Day Date: Mon, 27 Oct 1997 12:59:10 GMT Organization: New Jersey Medical School In article , ronda@panix.com (Ronda Hauben) wrote: > An article in Saturday's {New York Times} (10/25/97) "Internet's Value > in U.S. Schools Still in Question" (page 1) described the 2nd annual > netday and showed the prejudice of some of the press against the > educational use of the Internet. While the {New York Times} has had > many glowing accounts and hype about how the Internet is crucial for > business and the commercial world, when it comes to describing or > discussing the importance of the Internet for schools, they have > trouble finding reasons to support the educational development and > spread of the Net. Counter-examples? I, for one, am an advocate of using the Internet in schools where appropriate. What we're seeing today, though, is a headstrong rush into wiring all schools without understanding why this is so necessary. For me, it's a clear case of coders just deciding to do it, without the engineers figuring out what we're trying to accomplish. > They raise the question "Will the teaching of basic skills > be harmed or helped by the cyber-revolution?" giving the > impression that kids who can't use computers and the Internet > will be able to survive in a world where computers and the Net > are becoming an increasingly important part of the lives of those > who do have access. I don't agree. First, the issue is primarily about money. Vast sums of scarce educational resources are being spent to wire schools, many times depriving other programs of the resources to survive. Is Internet access more important than, say, art or music classes? Second, the Internet is a tool. It is not an end in itself. Certainly it is a great equalizer as it gives many people access to rich and varied information. However, without the basic skills to understand and appreciate what they can discover, it will end up being a great time-waster. > One wonders why the {New York Times} reporter doing the story > wasn't asked to interview teachers or students in the New York > City area who are using and finding the Net valuable. (Though New > York City does seem to be very behind other areas in the country > and world who are trying to get students access to the Internet > as soon as possible.) The cases of this are spotty, in my experience, which I admit to being limited. Only where an educator has gone to great lengths in his or her personal life to learn how to navigate the net are these results realized. The efforts to wire schools are so expensive that many schools have money for the access, but then spend a negligible amount of resources on training. For a similar scenario, check out how many schools have PCs running only Windows, with no applications, and the teachers never turn them on because they've never been trained to use them. > The story begrudgingly reported that "And many techers report > that writing E-mail to students in other communities and other > countries, for instance, seems to motivate students to want to write > and read." However, the NYT story basically fails to understand that > the importance of the Internet is "communication". That people are > able to communicate with each other and all gain in the process. > Instead the story seems to think of the Internet as only a one way > media with people being swamped by information they don't know how to > deal with. There needs to be more reasons to have every school wired other than writing email to one another. The educational gain here has not been proven, to the extent that it could be, from everything I've read. > It is disappointing to see such reporting continue by the {New > York Times} at a time when there is a great need among the public to > have real information about how the Internet is being used in schools > around the world (and the U.S. is quite backward in this regard) as > well as in the U.S. Instead it seems their pro commercial line that > the Internet should be reserved for business and making money has > interferred with their raising the necessary public questions as to > the appropriate public policy for the future development of the > Internet. Actually, I believe they're a voice of reason, saying "whoa, what are we spending all of this money for?" Certainly there are compelling reasons for doing this, lets just make sure we've got our eyes open and our priorities right. "Because everyone's doing it" should not be the reason when monies for education are so scarce. For me, I would much rather see schools getting wired for the teacher's benefit. Educators typically communicate within the confines of their own building or, at best, local school district. To give them a tool to enrich their classroom and coursework makes sense to me. Then, once the advantages are more clear, you would have an environment that would allow teachers to start using the technology as an instructional aid. Computers haven't been the silver bullet to improving education that everyone thought they would be. We should move very cautiously when spending more educational dollars on technology without some clear direction and proven results. Thomas G. Spalthoff spalthof at umdnj.edu ------------------------------ From: varney@ihgp2.ih.lucent.com (Al Varney) Subject: Re: Signaling, Routing and General Confusion Date: 27 Oct 1997 04:51:34 GMT Organization: Lucent Technologies, Naperville, IL Reply-To: varney@lucent.com In article , Brian Silver wrote: [dials number located on another switch, then...] > So, my CO switch then *finds the next switch that it needs to send the > address information to*. > Question #1. How does this happen? My understanding is that based on > the number, the switch has a routing table that tells it based on time > of day, and trunk availability what switch to go to next. So if the > switch sees an area code, it knows "Hey, that call needs to go > InterLATA, so this is the next switch in line", if it sees an > exchange, it knows based on that what trunk to use. Right? Just switch > configuration, or does SS7 have something to do with this? In most cases, the "routing table" is queried using the first three digits of the dialed number (while you are dialing the remainder of the number), and the information from that particular entry in the table is examined. If you are dialing a seven-digit number (as determined from the entry), the switch patiently waits for you to finish dialing. The entry would also supply a "route index". This is used to look up the first-choice trunk group (group of circuits to a common destination) to the next switch. Also, the type of charge record would be determined from the entry. If the first three digits appear to be an NPA, the entry may indicate to reject the call or may indicate seven more digits are needed. This decision is also affected by "prefix" digits (0, 1, 10XXX, etc.) that you may have dialed. So "222" may be recognized as an office code, but "1+222" may be recognized as an NPA. Also, the entry in the routing table may indicate "interLATA" based on only the particular NPA, or may indicate that three more digits must be examined before determining the "interLATA", "route index" and type of charge for this call. SS7 is a signaling mechanism -- it isn't involved in the decision of trunk selection. > Ok, so the first switch now knows what switch to go to next. It must > signal that switch, telling it it has an incoming call. Now, I think > there are a number of signaling methods, but lets focus on Robbed Bit > and SS7 and MF. My understanding is that using MF signaling, the first > switch would assert the proper tone on the trunk to the next > switch. Does this happen in one time slot in a TDM trunk? If the > signaling is robbed bit, does it just assert the bit? I'm a bit > unclear on how signaling happens on T-carrier trunks. Ahh, Signaling. Confusing term by itself. In telephony, there is Address Signaling and Supervision Signaling. You have to know from context which is being discussed. Sometimes Supervision Signaling is just called Supervision. Address Signaling may be called Outpulsing when applied to trunks. On your touch-tone (officially DTMF) line, you signal Supervision by going off-hook (a change in current flow in the line). You signal Addresses using pairs of AC tones that are interpreted as keypad digits. On MF trunks, Supervision is signaled using a variety of methods. Switches may use two extra leads (E&M) to signal over, but the circuit outside may use in-band tones or current reversals or what-ever to actually reach the other end. On digital MF circuits (your TDM trunk), robbed bits are typically used for signaling Supervision. There are actually two (A&B in SuperFrame) or four (ABCD in Extended SuperFrame) signaling indicators available in each direction for each 64kbps channel. Address signaling uses pairs of tones, different from touch-tone, and signals these tones over the channel used for the call, prior to connecting you to the channel. This is called in-band signaling. > Also, how does this happen using SS7? Does the first switch send a > request to an STP, and address the information with just the > destination phone call? How does SS7 tell the first switch what trunk > the call needs to go out? I'm a bit confused when it comes to call > routing and SS7. Does SS7 even play any role in call routing? SS7 is for signaling (both Addresses and Supervision). Routing is something a switch does inside itself. (Well, CCIS6 was an exception, but it's no longer used.) Think of routing as picking a trunk based of digits. SS7 identifies switches (and other nodes) using Point Codes (like IP Addresses). Trunks are identified by Circuit Id Codes (like port numbers) plus the Point Codes at each end. Once routing in the first switch identifies an idle trunk in the appropriate trunk group, it also knows the Circuit Id and far-end Point Code of the next switch. This information is sent to an STP, along with the Called number, the Calling number, Billing information, desired Bearer Capability, etc. The STP uses the destination Point Code to determine where to send the message. The switch receiving this message will locate the appropriate incoming trunk based on the Circuit Id Code. > Ok, so the first switch signals the second, and then second winks > back, telling the first that its ready for address information. This > process happens all down the line until the last switch is reached. True for MF signaling -- SS7 doesn't usually send anything to the preceding switch until destination switch is reached and an idle line is rung. If busy, the originating switch will just get a RELease message with a "user busy" cause value, play a busy tone to the caller and idle the outgoing trunk. > The last switch then says "Ah! This call goes to this number, and its > on me!". I assume that switches are configured to tell the switching > tables "This number == This Line" The incoming address is translated through the routing tables. In the case of a terminating number, the routing table entry will be something other than a "route index". Usually it is associated with an office code. Other tables are then used to identify the actual line based on telephone number. > Now here is where the fact that I'm calling my ISP comes into play. My > ISP gets a T1, lets say. The switch then hunts for a TDM slot on the > trunk for the call, right? And it uses robbed bit signaling (unless > ISDN, when it uses Q.931 ...). > Question #2. (Ok, more like question number 800 ...) Does the single > bit for signaling represent the presence/absence of the old-fashioned > 2600Hz tone? The way I see it working is the ISP RA box sees the > signal bit on the incoming DS0, and knows to pick up the phone > (equivilent of a ring). But how does off-hook get signaled? If you mean off-hook from the ISP end, it has its own signaling bit(s). Digital facilities have two independent directions of transmission and signaling. (2600Hz only worked for one-way trunks). For digital trunks, the ISP would recognize a particular A/B bit pattern as "alerting to you" and the ISP would signal the switch with an A/B bit pattern that means "I'm ready for the call". The patterns will differ depending on call direction and the particular type of interface. > .... All the books I have read separate routing and signaling, but > it seems to me that the two are somewhat linked since MF signaling set > up the route at the same time the signal was propagated. Nope, MF signaling is used AFTER a route is selected. Routing and signaling can be thought of in a switchboard context. Routing is what the operator does in figuring out which jack to plug into. Signaling is what the operator does AFTER the plug is in the jack, exchanging information with the other end of the connection. You ROUTE (figure out which phone to use). You SIGNAL (off-hook, digits). The switch receives SIGNALs, ROUTES (picks a trunk) and SIGNALS (sends off-hook, address, winks). Next switch receives SIGNALs, ROUTES (picks a trunk or terminating line) and SIGNALs (sends off-hook or ringing, etc.). I'm not sure how routing (selection of a facility) can overlap with signaling (setup over a facility). You could look for some books by Amos Joel if you want more information on telephone switching history, which is where most of the current terminology originated. Al Varney ------------------------------ From: John Driscoll Subject: Re: Tower Site Leases Date: 27 Oct 97 05:30:07 GMT Hi Allison; Having done this for a few companies, I can give you answers relative to the greater Boston area. Average term is for five years on an existing structure, longer terms if the carrier must build their own tower. Both normally have multiple renewal options for a length equal to the original term. Average rental value can vary widely, there is much wheeling and dealing, but for existing structures in Boston it ranges from $2000 to $3000 per month with annual CPI increases of no less than 5% (for a full blown PCS/cellular site, less for 'micro-cells'). Where the carrier must build a tower and lease the land, it can also vary widely, but it is generally much lower: $500 - $1500 per month depending on location. Government property is usually the same, although Federal property I have not dealt with. I would also recommend that anyone contemplating doing business with a carrier use their own lease - the carriers lease is usually very restrictive and can cost the property owner money. One carrier in Boston used a lease which stated that any future tenants must be approved by them -- which approval was generally denied for anyone they considered a competitor! ------------------------------ Date: Sun, 26 Oct 1997 21:20:44 -0800 From: Marty Bose Subject: Re: Tower Site Leases I'm disappointed to see TELECOM Digest publishing a troll request like this one. When I worked for a PCS carrier this was a typical request from a lawyer trying to find a way for his client to bust a lease that the owner had second thoughts about. On the average they would come back and request a new lease at four to ten times the original lease, usually after construction had started. I hope that no one will respond to this, as this guy may go to work for one of your clients next! Marty Bose ------------------------------ Date: Mon, 27 Oct 1997 08:09:00 -0500 From: Bob Keller Subject: NiCad Memory Effect (was: New Cellular Phone Experience So Far) In TELECOM Digest V17 #284, Brett Frankenberger wrote: > This is a very common, and very unsubstantiated, urban legend. > Under carefully controlled laboratory conditions, where you > repeatedly partially dischange the cells to the *same level* > each time, you can sometimes get a memory effect to appear, > after a lot of cycles. Under normal random usage, in which you > never fully discharge the batteries, but always discharge to a > different level, the memory effect does not appear. I would not go so far as to put "memory effect" in the urban legend category; it is something I have personally experienced under decidedly uncontrolled, non-laboratory conditions. Having said that, I have found that the compulsive need to "fully discharge" batteries actually causes more frequent and severe problems than the potential memory effect it is intended to prevent. Some users seek to discharge the pack to levels even lower than the point where the host device stops working properly. If you do that, one or more of the cells in the pack can actually reverse polarity. If the overall pack reverses polarity you are really in a fix. Not only is the pack virtually useless at that point, it can damage equipment to which it is attached (depending on the nature of the equipment). That is one of the reasons why: > (Also, most newer phones won't fully discharge the cells, prefering > instead to shut themselves off when the voltage drops below a certain > level.) Bob Keller (KY3R) rjk@telcomlaw.com www.his.com/~rjk/ ------------------------------ From: lwinson@bbs.cpcn.com (Lee Winson) Subject: Re: InTRA-LATA Carrier Verification Date: 27 Oct 1997 01:37:11 GMT Organization: The PACSIBM SIG BBS Calculating local and near-local calling costs must be tough, especially when considering competitive carriers, in regards to the posting. First off, as I see it, in the Phila area you have at least three classes of calls: Purely local: In the "measured use" table, this are those marked 1 unit. The main thing is these calls cheap and also UNTIMED. If you are routing calls through an alternative carrier who times you, you could potentially pay more -- depending on your call mix. (If you make a lot of quick brief calls, this could not apply.) Measured Service: These are those within the "Metropolitan Philadelphia Calling Area", which is the City of Philadelphia and nearby suburbs. The phone book has a map and list of towns/exchanges. For these calls, you have to balance your carrier against the Measured Service table. Timings vary by distance and time of day. For high volume users, you'd probably need to do a computer analysis, figuring every single call by Bell's rates and the competition's rates. The differences are cents, but at high volume it adds up. In the old days, some businesses would have foreign exchange lines so their customers could call them for free and likewise. Generally, a suburban location would have a city number. Plenty of businesses still do this Toll service: If the call goes beyond the "Metro Phila Calling Area", it's toll. Does anyone know if Bell Atlantic offers business customers deals on measured service or toll? Residential customers, for a steep price ($40-50 per month) can get unlimited Metro area calling. ------------------------------ From: Marty Tennant Subject: Re: InTRA-LATA Carrier Verification Date: Mon, 27 Oct 1997 20:35:47 -0500 > At one point, Worldcom told us to dial 700-4141 (we're in area code > 610) to verify our inTRA-LATA toll PIC assignment. I did; it works > just like (700) 555-4141. > I've never seen that mentioned here; does it work anywhere else? I tried dialing only 700-4141. No go, "your long distance carrier cannot complete your call as dialed". I then tried 1-803-700-4141, since I am in NPA 803. It worked, but said "thank you for using GTE". GTE is not my intralata carrier, but they are my local exchange carrier. I don't get bills from them anymore for intralata, but they tried to bill me once for a call that was also billed by my real intralata carrier. Never could figure that one out. Anyone else with intralata presubscription out there with anything to report on this new verification code? marty tennant - president - low tech designs, inc.(tm) "Bringing Technology Down to Earth"(sm) 1204 Saville St., Georgetown, SC 29440 803 527-4485 voice / 803 527-7783 fax ------------------------------ Date: Mon, 27 Oct 1997 06:48:42 -0500 From: blw1540@aol.com (Bruce Wilson) Organization: AOL http://www.aol.com Subject: Re: Is Southwestern Bell Allowed to do This? In article , ravip@utdallas.edu (Ravi Prakash) writes: > My question is: Is Southwestern Bell within its rights to disconnect > the telephone? After all, he provided them will all the identification > information they requested. Isn't it their responsibility to verify > the information? Moreover, he has never defaulted on any bill > payments. Questions such as this should be directed to the state Public Service/Utility Commission which regulates such matters. The staff can advise the customer how far the company's permitted to go and intervene if it's gone too far. Bruce Wilson ------------------------------ From: raphael@willy.cs.mcgill.ca (Louis Raphael) Subject: Re: Is Southwestern Bell Allowed to do This? Date: 28 Oct 1997 05:22:50 GMT Organization: McGill University Computing Centre Ravi Prakash (ravip@utdallas.edu) wrote: > My friend has applied for his social security number. But, the card > hasn't arrived yet. Moreover, since getting the telephone connection, > he has been regularly paying all the telephone bills. Aren't SS#s supposed to be for tax purposes, and *not* for this kind of stuff? My guess would be that they've got absolutely no business asking for this kind of information. > My question is: Is Southwestern Bell within its rights to disconnect > the telephone? After all, he provided them will all the identification > information they requested. Isn't it their responsibility to verify > the information? Moreover, he has never defaulted on any bill > payments. The way things are done here is that if you aren't considered "trustworthy," you can be made to make a deposit as a guarantee that you'll pay your phone bill. I would assume that the telco is *not* within its rights to deny service so easily, as a regulated utility. I suggest that your friend check with the Texas PUC for an answer. BTW, I take it that telco isn't also his LD provider -- and that's probably the only place that they can really take a significant loss. Possibly, they'd be reasonable and accept a small deposit as security, but somehow I doubt it ... Louis ------------------------------ Date: Mon, 27 Oct 1997 12:50:41 -0600 From: Jason Forst Reply-To: forst_NO_@us.ad_SPAM_vantis.com Subject: Re: Phone Problems in Nebraska? TELECOM Digest Editor wrote: > I needed to call someone in the Omaha, Nebraska area (actually west of > Omaha about forty miles) on Sunday and after several attempts to get > through and getting only busy signals, fast busies or nothing at all I > found out that phone service was at a crawl in that area due to a very > massive storm Saturday. Apparently two or three feet of snow, some > extremely high winds and other conditions knocked out a lot of > circuits. Does anyone have an update? I guess this condition was all > over that area with Colorado also affected quite heavily. Pat, I grew up in OMA, and talked to a close friend there on Sunday morning. They had about 12-16 inches of very wet and heavy snow, and since the trees had not yet lost their leaves (very little turn in color, in fact) the trees suffered very heavy loading, causing very large power outages as the trees collapsed. My freind had been without power for awhile, and was surprised that the telephone was working. The inter-office plant in the area used to mainly be on arials, but that was a number of years ago (ten). I also have relatives in the Des Moines area, one had phone service, the other, in a small town about ten miles west, did not. The number out of service was busy always. This is the same as an earlier confirmed outage, where USwest actually remote forwarded the residential line to a business so that calls could be completed for the residential customer. This went on for a few days. Anyway, most probably weather related. jason ------------------------------ Date: Mon, 27 Oct 1997 06:48:44 -0500 From: blw1540@aol.com (Bruce Wilson) Organization: AOL http://www.aol.com Subject: Re: Phone Problems in Nebraska? In article , ptownson@massis.lcs. mit.edu (TELECOM Digest Editor) writes: > I needed to call someone in the Omaha, Nebraska area (actually west of > Omaha about forty miles) on Sunday and after several attempts to get > through and getting only busy signals, fast busies or nothing at all I > found out that phone service was at a crawl in that area due to a very > massive storm Saturday. Apparently two or three feet of snow, some > extremely high winds and other conditions knocked out a lot of > circuits. Does anyone have an update? I guess this condition was all > over that area with Colorado also affected quite heavily. Des Moines got about 6" of VERY WET snow, with areas to the south of it getting as much as 10" of the stuff. With the trees still full of leaves, trees were snapping and falling all over the place, often taking utility lines with them. (We were without power for about 11 hours; and some areas of town won't have service restored until sometime Monday.) Reports are that some areas of Colorado got something on the order of 4 FEET of the stuff; and it seemed something like 80% of utility customers in Omaha-Council Bluffs were without power at one time. The only positive aspect of the situation is that daytime highs are to start in the 40s and move up to the 50s by the end of the coming week, so we'll have the snow out of the way while we're cleaning up the mess. Bruce Wilson ------------------------------ Date: Mon, 27 Oct 97 06:38:21 GMT From: gashley@uswest.com (Greg C. Ashley) Subject: Re: Phone Problems in Nebraska? Pat, things are pretty bad here in Omaha. I think we've got as much damage (or more) than was caused by our famous May, 1975 tornado. Hopefully we'll get on top of it fairly quickly. Greg C. Ashley gashley@uswest.com Mass Markets & Design Services Analyst NE/IA US WEST Communications, Inc. Omaha, Nebraska ------------------------------ End of TELECOM Digest V17 #293 ******************************