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Aucbvax.2818 fa.telecom utzoo!decvax!ucbvax!telecom Wed Aug 26 02:13:06 1981

>From geoff Wed Aug 26 02:13:01 1981 >From poli-sci Tue Aug 25 21:10:52 1981 Subject: TELECOM Digest V1 #1 Newsgroups: fa.poli-sci Status: R

>From JSol@RUTGERS Mon Aug 24 22:25:21 1981 TELECOM AM Digest Tuesday, 24 Aug 1981 Volume 1 : Issue 1

Today's Topics: Administrivia - Welcome Aboard USRNET - Alternative to A. T. & T. Problems with Dimension - One Persons Views ----------------------------------------------------------------------

Date: 24 Aug 1981 0118-EDT From: the Moderator <JSOL AT RUTGERS> Subject: Administrivia

Welcome to TELECOM. This digest is a spinoff from the HUMAN-NETS discussion on the telephone network and switching equipment. Parts of this digest are in fact submissions to HUMAN-NETS which were never published, and are presented here to spark the discussion.

The archive for this is in the usual place, DUFFEY;_DATA_ TELCOM at MIT-AI, and we will shortly be adding to the archive the discussions that have taken place in HUMAN-NETS relating to telecommunications.

I will be moderating this list from Rutgers, as I do with POLI-SCI, but you can still send mail to TELECOM@MIT-AI, or TELECOM@RUTGERS. If you want to communicate with the maintainers then you should send mail to TELECOM-REQUEST@MIT-AI, or TELECOM-REQUEST@RUTGERS.

Enjoy, JSol

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Date: 12 Aug 1981 1257-PDT From: Daul at OFFICE Subject: USRNET

I was wondering what kind of information is sitting in the readership's minds regarding the proposed Shell's inter-company Usrnet. This is the alternative to the high cost of AT&T's services. Any information is welcomed. -Bill (DAUL@OFFICE)

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Date: 21 Aug 1981 1109-PDT From: Jwagner at OFFICE Subject: One writer's problems with Dimension

This editorial recently appeared in the San Jose Mercury, the local newspaper for San Jose CA and vicinity. It discusses one writer's problems with a new in-house telephone system. I'm sending it along without comment with the hope that it will spark a flame or two. -- Jim Wagner/jwagner@office

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GIVE HIM A RING -- IF YOU DARE (c) 1981 San Jose Mercury

by John Askins, editorial writer

Remember how it started out? The machines were supposed to be the servants and we were supposed to be the masters? Right now I figure I'm working for machines about half the time. The computer I type on decides that we're going to take a little break, and we take a little break. Never mind if I want to or not. Never mind if it's DEADLINE or not. When the remaining humans here want to tell me something quickly, they don't come running over to my desk. They flash a message across my screen. Sure I know it's them, but it feels like it's the computer getting all excited over something. It's unnevering. I'm not complaining, it's just that slowly and surely I'm losing my sense of, well, human dignity. Just this week we've been getting used to a new telephone system called Dimension which is supposed to make our jobs easier. They always say that, don't they? My telephone now does a lot of tricks. "Dimension is a system that listens to what you tell it and then talks back you you," said the Pacific Telephone representative sweetly. Just what I wanted, a phone that talks back to me. It has a lot of abilities, I'll give them that. All things that humans used to do, using English. It can forward all my calls to another number, or it can forward them only while I'm busy on another call. It can let me know I have a call waiting, and how important the caller is. It can put me in line for a WATS line and then call me back when the line is free. In other words, it's another goddam computer. You talk to it in simple number codes and it responds. It not only does what you tell it, but it has a limited vocabulary of its own, a sort of dial-tone Morse code that you're supposed to learn to interpret into English. Three short beeps means "Action accepted, proceed." Siren intercept, which sounds like a cop car responding to a riot call, lets you know you made a mistake. Three shorts and a long, followed by a dial tone, indicates that you didn't depress your switchhook properly. Yes, it's come to this. If I depress my "switchhook" -- the button under the receiver that I used to cal "the button" -- too quickly or slowly, the telephone is not happy. It is a sensitive "instrument," as the call it now, and I've got to learn new habits to avoid offending it. Pardon me, telephone sir. I don't want to be a bother or anything, but I'd like to make a call. If it wouldn't be too much trouble. At the training session, the nice woman (yes, they're still using people for some jobs at Bell) got up and explained to us that the days of just casually picking up the phone and using it, without paying too much attention to what you're doing, are OVER. For one thing, you have to make sure to hold the receiver real close to your ear, so you won't miss anything the telephone says. This training session was marvelous. Can you imagine spending an hour and a half to learn how to use the telephone? They had a color movie, a lecture, a practice session, everything but a quiz. And believe me, with Dimension you NEED it. A few days later they installed the system. Monday morning the phone rang in its new, authoritative way. Ring, ring. Ring, ring. I stared at it in horror, a jumble of codes flashing through my head. Finally I got up the nerve to lift the receiver expecting to hear a warbling siren intercept. There was nobody there. It had just been testing me. Later I tried to hang up by pressing the, let's see, switchhook, and got three longs and a short. "Scotch and soda!" I said quickly. "Scotch and SODA, goddammit!" Didn't do a bit of good. I finally replaced the receiver of my instrument and waited five minutes or so to get over being mad. Sure enough, there was a dial tone again. At least it doesn't hold a grudge. Well, so, big deal. New technology comes along and tells us we have to change our way of doing things. This is nothing new in the workplace. It's just that -- The typewriter, OK, I remember how reporters complained when electric typewriters replaced manuals, and how we complained again when video display terminals replaced typewriters. But at least these machines have a little class, a little allure. But a stupid telephone? Hell, I remember when their dials took forever to spin back around. I remember when all they were were devices for letting people talk to each other without being in the same room. Those were the good old days. Last week.

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Gumby@MIT-AI 08/04/81 19:24:28

After all that phone discussion, can anyone dissect the digits in an international direct-dialing sequence? I just called my parents direct (in Australia) and it was 14 digits including 7 of the australian number and a # at the end. What was the # (pound sign) for? david

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JSOL@Rutgers 08/24/81 00:49:00

You can look in your phone book for the explanation of international calling. If not there, the local phone store distributes free "calling guides" for international calls. Perhaps someone has a synopsis handy (Lauren?) and can provide a brief explanation, if you tell us the phone number you called then perhaps we can break it down.

Telephone numbers in the U. S. have an Area Code (3 digits), and phone number (7 digits). Sometimes you have to dial a "1" or something to get outside your "local calling area", but the switching system need only count the digits and then when you get all of them start completing them. International calls aren't so lucky. The number of digits can vary quite a bit, so the switching equipment times out if you don't dial any more digits and then tries to process the call with the digits it has. This timeout takes a few seconds. Touch Tone(tm) users with the # key can hit that at the end of the sequence to force it to complete the call, saving time.

JSol

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Date: 28 Jul 1981 1358-PDT From: Daul at OFFICE Subject: Phone Company Deregulation

What are the details (general or specific) on the phone company de-regulation? What are the rumors about MacDonald's wanting to buy in?

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Date: 28 May 1981 17:52:28-PDT From: ihnss!hobs at Berkeley To: ucbvax!HUMAN-NETS@MIT-AI Cc: ihnss!hobs@Berkeley, ihnss!wlh@Berkeley

Subject: ESS

I want to correct some erroneous statements that I made about the ESS machines. (I bet Lauren beats me to it.)

#1/#1A is a large local switch (100K lines or so), #2/#2B is a medium local switch (30K lines), and #3 is a small local switch (12K lines?). #4 is a TOLL switch, it handles no lines but up to 107K trunks. Both #4 and #5 use a digital network to perform the actual switching, the others use an analog network. #5 will handle up to 100K lines by adding capacity on a modular basis. The first #5 is currently scheduled to go into service late this year. May you be spared egregious errors, John

[This discussion of ESS telephone switching picks up from HUMAN-NETS Digest V3 #108. Shortly a transcript of the entire discussion should be made available in the archive at MIT-AI. -JSOL]

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Date: 28 May 1981 14:54 edt From: JSLove at MIT-Multics (J. Spencer Love) Subject: #5 ESS Sender: JSLove.PDO at MIT-Multics cc: JSLove.PDO at MIT-Multics

A recent message to Human-Nets contained a slight inaccuracy on this subject: The #2 ESS is used in rural applications, and the #4 ESS is used in toll switching only (not in rural offices as stated). The characteristics of ESS machines that I can remember easily are:

#1: A sort of glorified crossbar machine that uses banks of reed relays (called ferreed switches) of some sort arranged in the same way that the old crossbar switches were used. It also uses some fancy magnetic technology switch that are polled in a manner reminiscent of core memory to detect on/off hookness and pulse dialing. It is controlled by a multiply redundant (2.5x) 40-bit computer running out of a vast quantity of magnetic(?) read only memory. In short, it appears not to have used ANY off-the-shelf computer technology at all.

#2: A smaller machine that uses time-domain multiplexing to switch conversations around withing itself, using an 8KHz sampling rate to provide the 3.6KHz bandwidth that TPC generally delivers. With a capacity of about 2000 subscribers (as opposed to 40,000 for #1) it is generally intended for rural or other small-capacity application. Much of the hardware of the #2 has also appeared in the automatic intercept machines: the ones that deliver you individualized recorded sorrow when you reach a nonexistent number. I think the computer is a more relatively conventional 16-bit architecture.

#4: This machine handles 4-wire interconnections. That is, completely separate pathways for the two directions of a conversation. The #2 is internally 4-wire, but externally 2-wire, and the #1, when used in regular central offices at least, is 2-wire. There were some crossbar machines that were built 4-wire, so there may have been some #1's built that way for similar applications. 2-wire technology is fine for voice grade, short haul interconnections, and is commonly used in intra-city communications, but problems with echoing caused by impedance mismatches cause 4-wire technology to be used in most long-distance network equipment. Unfortunately, echo-suppressors are still needed in many cases because the ends of the conversations are on 2-wire equipment with sloppy impedance matching. The #4 is also an all-digital switch. All kinds of signal processing problems plague designers of analog telephone switching equipment, and their less than perfect handling of these problems is the reason that many long distance connections are so bad. By first digitizing the signals, parts of the long distance network preserve the signals from any further distortion until they reemerge into the analog world at the other end of the conversation. When the #4 ESS was designed, this was too expensive for central office use, but looked very good for the long distance network.

There may be minor inaccuracies in this presentation since it has been years since I payed serious attention to these issues. I don't know what the #3 ESS is (if any), and I can't remember any other convincing applications for 4-wire technology in the scale appropriate to a telco central office.

Based on the above, I would guess that the #5 ESS is an all digital (and hence internally "4-wire") switch with a modular design and sufficient "distributed intelligence" that it can fit equally well into the small (#2), midrange (#1) or gigantic (#4) offices. When connected to actual subscriber loops (wires leading to telephones), it probably uses CODEC's (like MODEM: modulator/demodulator, except encoder/decoder), which have become cheap enough that having one for every phone line is now feasible. You can buy them as single integrated circuits, these days.

This has the additional implication that four wire circuits to subscribers will become quite cheap in such exchanges (although it may be years before the rates reflect this). This has great implications for data communications, since the CODEC for a given line might be replaced with a pair of short-hail MODEMSs, at a great saving in bandwidth and an eventual reduction in data-communication rates.

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End of TELECOM Digest ********************** -------

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