TELECOM Digest Tue, 21 Feb 95 15:12:00 CST Volume 15 : Issue 112 Inside This Issue: Editor: Patrick A. Townson Re: Pair Gain Line Problem, Help! (Bennett Wong) Re: What is Loop Start? (Martin McCormick) Re: What is Loop Start? (William Wood) Re: What is Loop Start? (Wally Ritchie) Re: What is Loop Start? (Sharon Prey) Re: Pre-Paid Phone Cards - Evening Rates? (Jeffrey Kagan) Re: Pre-Paid Phone Cards - Evening Rates? (Cliff Lam) Re: Pre-Paid Phone Cards - Evening Rates? (Shawn Gordhamer) Re: Motorola Flip Phone and Low Battery (David Chessler) Re: Motorola Flip Phone and Low Battery (Shawn Gordhamer) Re: Motorola Flip Phone and Low Battery (Ry Jones) Re: What is DMS-100? (Sharon Prey) Re: What is DMS-100? (Greg Habstritt) Re: What is DMS-100? (Mike Boyd) Re: Area Code/Prefix Trivia (Philip V. Hull) Re: Area Code/Prefix Trivia (David W. Tamkin) TELECOM Digest is an electronic journal devoted mostly but not exclusively to telecommunications topics. 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Any organizations listed are for identification purposes only and messages should not be considered any official expression by the organization. ---------------------------------------------------------------------- Date: Tue, 21 Feb 95 08:56:16 PST From: wong@pairgain.com (Bennett Wong) Subject: Re: Pair Gain Line Problem, Help! > I have been told by a Pac Bell (i'm in CA) tech that the reason that I > cannot connect above 9600 is because I'm on a "Pair Gain" line to the > C.O. My roommate has no problem, the tech says he's on a copper line > to the C.O. > Problem: Pac Bell refuses to change me over to a copper line, saying > that they are only required to provide a 'voice-grade' line which only < has to support transfer speed of 1200 bps (HA HA HA HA HA). Matt, I can't offer any specific advice, but I can give you some information that might be helpful. Assuming that by using the term "Pair Gain" you mean that Pac Bell has you on an AML line, you're probably on an analog "added main line". My tech guys tell me that the most you will probably get is 2400 baud. If you're on a digital AML, then you should be able to go above 9600 baud with no problem. The company that I work for, PairGain Technologies, sells a digital AML called PG-2 that can support dialup modems at speeds up to 19.2 kbits/s with no problem. (It may be able to support higher rates, but 19.2 kbits/s is what they last tested a PG-2 unit at). However, my tech guys also tell me that Pac Bell doesn't buy any PG-2 units from us. Instead, they buy units from Rockwell, Wescom, and Adtrans. I don't know if these are digital or analog AML's, but it seems the trend is to not buy anymore analog AML's. Maybe you can ask your phone company to move you over to a digital AML (perhaps, from PairGain Technologies ;) from an analog AML. Hope this helps, Bennett Wong PairGain Technologies, Inc. 14402 Franklin Avenue Tustin, CA 92680 wong@pairgain.com ------------------------------ From: Martin McCormick Subject: Re: What is Loop Start? Date: 20 Feb 1995 19:45:31 GMT Organization: Oklahoma State University Stillwater, OK In article nagle@netcom.com (John Nagle) writes: > When a subscriber goes off-hook with intent to originate but > actually answers an incoming call, the situation called "glare" has > occured. This is a big problem for heavily-used lines used for both > incoming and outgoing calls, Where did the term "glare" ever get to be used in this context? Martin McCormick WB5AGZ Stillwater, OK OSU Center for Computing and Information Services Data Communications Group [TELECOM Digest Editor's Note: Imagine two motorists driving in opposite directions down a narrow one-lane road with no room to pass each other. They meet in the middle somewhere, and each one leans out the window and glares at the other, wanting *them* to the be one to back up and get out of the way. 'Glare' in the conventional sense means to look in a hostile fashion at another person. Two calls on one pair each going in the opposite direction are certainly hostile and/or incompatible with each other. A state law on the books in Kansas at the end of the 19th century detailed exactly how to handle the problem of glare, where railroad trains were concerned: "If two trains both on the same track approach each other from opposite directions, then each shall come to a complete halt and wait until the other train has passed entirely." Yes, that was a law in Kansas over a hundred years ago, repealed quite a few years ago when the Kansas legislature did a major overhaul and re-codification of the statutes of that state. In the case of telephonic glare, there is really no other option except for both parties to disconnect and start all over again unless the party on the inside line of the PBX is willing to be nice about it and try to transfer the call off his line and back to the attendant somehow, even though she did not give the call to him in the first place. PAT] ------------------------------ Date: Tue, 21 Feb 1995 10:38:52 -0800 From: wewood@ix.netcom.com (William Wood) Subject: Re: What is Loop Start? Paul Garfield (garfield@vanilla.cs.umn.edu) writes: > Long ago I remember terms like loop start and ground start as > different protocols for handling signaling bits on a T1 line ... Paul, it couldn't have been reeeealy long ago or you'd know that loop, ground, wink, etc. originated on analog lines (local loops from the dial tone switch, etc.) and trunks (facilities between switches). See ..... sometimes it pays to be old. The best way to look at your question is to begin by understanding that T type carrier is simply the transporter of signaling information. It doesn't do anything but extend the native signaling/supervision form of the equipment to which it is connected, which is (in voice applications) usually a switch, but sometimes private line equipment. The T (or any other type of carrier) is at its core nothing more than a distance extension methodology to allow devices such as telephones to be located beyond metallic circuit distances. The circuit signaling type is unrelated to the carrier system (other than its ability to transparently transport the supervision states). So, the first part of answering your question is to divorce the carrier from the signaling. The next part is just basic phone stuff relating to signaling and/or supervision. Loop start is the type of supervision generated by your local POTS (plain ol' telephone service) telephone set. The local serving dial tone switch applies (normally in the USA) -48v battery to one (usually the ring) of the wires in the pair coming to your phone. It applies switch ground to the other. When you go off hook, your telephone set connects the tip and ring wires together thus forming a "loop" from the switches' point of view. This loop starts the call process. Ground start adds one new wrinkle. In the idle state the switch still applies -48 battery on the (usually) ring wire but leaves the tip open. When you want to make a call your device (PBX or special phone) must first apply a local ground to the (usually) ring wire. This will cause current flow on that wire which the switch will interpret as a request for ground on the (usually) tip wire. From here on out the process works like loop start. We've always called this operation RING GROUND START because you have to ground the ring wire to start the dialing process. This process also helps prevent glare, but I'll leave that explanation for another posting. The other types of supervision you asked about are usually not line oriented. They are used on trunks. Wink just means a momentary off/on hook change which alerts equipment to follow on with some action. MF outpulsing is a good example of what happens after one switch sees a wink on a trunk from a distant switch. The word wink comes from an old type of signaling test box which had two lights that lit up when the line and drop were on hook. The lights would go out on off hook conditions. A momentary change from on to off and back to on would cause the light bulbs to blink or wink at you. Hope this helps - we have a two day on-site only seminar which covers these basic processes, if you re interested in more details. WE Wood Technotranslater Techtrans Animatics Group Techish to English Translations ------------------------------ From: writchie@gate.net Subject: Re: What is Loop Start? Date: 21 Feb 1995 06:06:09 GMT Reply-To: writchie@gate.net In , garfield@vanilla.cs.umn.edu (Paul Garfield) writes: > Long ago I remember terms like loop start and ground start as > different protocols for handling signaling bits on a T1 line (although > I didn't know the details). Recently I've seen the following terms > applied to ANALOG lines: loop start, ground start, wink start, earth > recall. What do these mean? I always thought all analog lines were > the same. The relevance to T1 is only that the AB signalling bits control the signalling functions performed in the particular channel units that provide the analog interfaces. The base definitions for the interfaces are analog. To summarize: Loop start is the regular POTS line where closing the loop signals off- hook to the Office and power ringing signals an incoming call. Disconnect from the office following an answered call is typically indicated by removal of battery (which dropped the hold relay on the once pervasive 1A2 key system. The major difficulty with loop start is that an incoming call can be connecting during the silent interval of the power ringing and it is possible to close the loop for an outgoing call during this interval. The incoming call will then be answered. This can be reduced by immediate ringing (connecting the line to an active cycle of power ringing immediately upon seizure) but this is typically not available. Ground start originates calls to the Office by grounding tip. Calls from the Office are indicated by tip ground (and power ringing). Ground start also provides positive disconnect indication from office under all conditions. Ground start is the typical analog PBX trunk interface. Wink Start is not a trunk type but a signalling protocol that can be used on Reverse Battery (DID) or E&M trunks. The wink indicates readiness to receive digits. The wink is a momentary offhook after which the originating end transfers digits by either pulse dialing or inband tones. Off-hook is returned when the addressed station answers. Reverse battery uses battery from the CPE with normal polarity indicating on-hook and reverse polarity indicating off-hook. Reverse battery is one way in to the CPE. The channel units are called DPO and DPT (Dial Pulse Originating and Terminating). Earth recall is the U.K. version of ground start. Perhaps someone on the other side of the pond can elaborate on this and other European Interfaces. Wally Ritchie Ft. Lauderdale, Florida ------------------------------ From: Sprey@ix.netcom.com (sharon prey) Subject: Re: What is Loop Start? Date: 20 Feb 1995 23:30:04 GMT Organization: Netcom In garfield@vanilla.cs.umn.edu (Paul Garfield) writes: > Long ago I remember terms like loop start and ground start as > different protocols for handling signaling bits on a T1 line (although > I didn't know the details). Recently I've seen the following terms > applied to ANALOG lines: loop start, ground start, wink start, earth > recall. What do these mean? I always thought all analog lines were > the same. Most of your regular phone lines are loop start; you pick up the phone and there is a loop or circle from the phone thru the equipment and back to you. Ground starts lines that require a ground on one side to give dial tone, and they may be business lines or lines other than the regular residential lines (they can be ground start but not usually). Loop and ground start are not just analog. Wink start is on a trunk or connection that requires the other end to send a wink. The wink is like saying it's okay to send digits to connect your call. [TELECOM Digest Editor's Note: Don't you think however that ground start lines are a lot more secure in applications like modem dial in lines or situations where the power could go off and concievably leave an inbound caller connected to your system with the ability to use one of your outgoing lines? PAT] ------------------------------ From: jefkagan@netcom.com (Jeffrey Kagan) Subject: Re: Pre-Paid Phone Cards - Evening Rates? Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Tue, 21 Feb 1995 13:57:27 GMT There is not a standard program. Some offer a time of day sensitive program, and others do not. You just have to sort through the different deals till you find the one that satisfies your criteria. Jeffrey Kagan * KAGAN TELECOM ASSOCIATES * Atlanta GA Telecommunications industry analyst, market researcher, consultant and speaker (404)419-2222 * PO Box 670562 * Marietta GA 30066 Internet Address: jefkagan@netcom.com ------------------------------ From: clifflam@interlog.com (clifflam) Subject: Re: Pre-Paid Phone Cards - Evening Rates? Date: Tue, 21 Feb 95 00:29:33 GMT Organization: interlog.com pwinston@cs.hmc.edu (Philip Winston) wrote: > I was thinking about tracking down some of those pre-paid phone cards > (even AT&T has them now I think) as a gift for someone. Are there other more attractive options for making long distance calls at pay phones without a bag of change or some form of credit card? I am interested in situations of placing calls from Canada to US, Europe, Asia and the Caribbeans. Cliff Lam [TELECOM Digest Editor's Note: Yes there are. For example AT&T's 500 program now allows what you are asking, and one equally as good or perhaps better is the 800 number service called 'My Line'. It also offers outdial capability. PAT] ------------------------------ From: shawnlg@netcom.com (Shawn Gordhamer) Subject: Re: Pre-Paid Phone Cards - Evening Rates? Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Tue, 21 Feb 1995 12:55:34 GMT pwinston@cs.hmc.edu (Philip Winston) writes: > [TELECOM Digest Editor's Note: They are a pretty lousy deal. Most charge > fifty cents per minute, in one minute increments. That's not surprising, > considering there are so many hands in the pot trying to cash in on them. > Many/most pre-paid card are multi-level-marketing things; everyone wants > a commission. For example, a couple years ago I experimented here with the > Digest readers with a type of pre-paid card called 'Talk Ticket'. For > two dollars, you got four minutes of time in increments of one minute each. > I paid, I think, $1.45 per card and resold them for the published price > of $2.00. Whoever I bought them from got them for about 85 cents each > I believe. A unit is a unit is a unit; day or night, weekdays or Sundays; > it does not matter. You could also, if desired, spend the four minutes > on the extra features offered such as voicemail, news weather and sports, > hot chat on a conference bridge, etc. > Prepaid cards are promoted as a way to allow someone to use your telephone > card a limited amount of time -- presumably for calls made to you -- without > the worry of that person abusing your regular card. They are also promoted úÿ > as a way to greatly reduce toll fraud, since if you lose the card or get > shoulder-surfed at the train station all stand to lose is the remaining > balance on that card. Those are good reasons, but the other side of the > coin is you pay so much for them by comparison. I put prepaid phone cards > in the same category as American Express or Traveler's Express Money Orders. > You pay them money for the privilege of lending them money until you > get around to cashing it in. Well, UpFront @ 1-800-888-3510 is a pretty good deal for a prepaid card. I know NOTHING about the company, if it's an MLM. I just called the company and they sent me a card. You can recharge it with check or credit card. Rates are $.20/min day, $.16/min eve, and $.13/min nite, anywhere in the US, including IN YOUR OWN STATE. This last point is better than a lot of calling cards. There is a $.10 surcharge per call though. I plug this company because I like the rates; I have nothing else to gain. If someone knows something more about UpFront, please post. I'm curious. Shawn Gordhamer shawnlg@netcom.com [TELECOM Digest Editor's Note: It sounds like a decent deal. Anyone from UpFront out there care to comment? PAT] ------------------------------ Subject: Re: Motorola Flip Phone and Low Battery From: david.chessler@neteast.com (DAVID CHESSLER) Date: Tue, 21 Feb 95 02:49:00 -0500 Organization: Online Technologies, Inc. - 301-738-0001 Reply-To: david.chessler@neteast.com (DAVID CHESSLER) > My instructions for my xt-pak ni-cad batteries say to maintain long > lifetime, I should discharge them fully before recharging (all the > time, not just the first five times), so I've found I must stuff the > phone under the couch cushions overnight so it won't wake me up. > Maybe this is an opportunity for a third party product - a cell phone > silencer (sound proof box), or a battery drainer (something that just > puts a load on the battery until it drains completely). I've handled ordinary nicads by putting them in a flashlight, turning it on, and waiting for the light to go out. With a cellular battery of peculiar voltage and conformation, just build a small battery-drainer on a scrap of pegboard, using a flashlight bulb of appropriate size. david.chessler@neteast.com chessler@capaccess.org chessler@trinitydc.edu ------------------------------ From: shawnlg@netcom.com (Shawn Gordhamer) Subject: Re: Motorola Flip Phone and Low Battery Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Mon, 20 Feb 1995 18:49:49 GMT I remember reading an article about cellular phone programming where there was a way to select the voltage at which the phone beeps or goes off. If I got it right, you could change the voltage so that it would never have a chance to beep before the phone died. Maybe this was only for when the phone powers off. I don't have the article any more. I wish I did, since I now have a Motorola! Shawn Gordhamer shawnlg@netcom.com ------------------------------ From: rjones@rjones.oz.net (Ry Jones) Subject: Re: Motorola Flip Phone and Low Battery Date: 21 Feb 1995 10:36:22 GMT Organization: The SenseMedia Network, http://sensemedia.net/ Patrick Wolfe (pwolfe@mcs.com) wrote: > My instructions for my xt-pak ni-cad batteries say to maintain long > lifetime, I should discharge them fully before recharging (all the > time, not just the first five times), so I've found I must stuff the > phone under the couch cushions overnight so it won't wake me up. Buy some Ni-MH battery packs. My fat pack lasts about 12-18 hours. I bought a trickle charger for my car and use the battery conditioner at work. It discharges and recharges in a few hours. And, I think if you turn the volume of the ringer down, it might affect everything else. I don't recall. ------------------------------ From: Sprey@ix.netcom.com (sharon prey) Subject: Re: What is DMS-100? Date: 21 Feb 1995 23:21:53 GMT Organization: Netcom In stahara@xlate.hsc.usc.edu (Stanley Tahara) writes: > Can someone give me some information? > I just got a letter from Pac Bell stating that on 10 March they are > going to install DMS-100 at the Los Angeles Central office and that my > prefix would be affected. The letter also states: > "... If you have other equipment connected to your telephone, such > as an answering machine or a computer, you may want to contact the > manufacturer or thee dealer from whom you purchased the equipment. > Some devices need to be adjusted so they will function properly with > our new switching equipment." DMS-100 is a Northern Telcom digital switch. They may be replacing an older switch or just upgrading the DMS. You shouldn't have any problems attaching your modem to your phone line. sprey ------------------------------ From: gregicg@cadvision.com (Greg Habstritt) Subject: Re: What is DMS-100? Date: 21 Feb 1995 01:14:51 GMT Organization: Intellitech Communications Group > I just got a letter from Pac Bell stating that on 10 March they are > going to install DMS-100 at the Los Angeles Central office and that my > prefix would be affected. The letter also states: > What can I expect in the way of problems, if any, using a modem to > send or receive call? I would guess you won't have any problems at all in the conversion. It sounds like a typical phone company, warning people that their lives may change as a result of work they are doing. A DMS-100 is a Northern Telecom "switch" that is installed in the CO. It's the actual switch, controlling all network in that particular area (as they say, "within that switch"). Sounds like they have to add another switch because they need more capacity that what they have installed presently. Other than your prefix changing (prefixes generally can't be shared across switches ... Centrex is an exception), I wouldn't expect much else to change. Bottom line is that plain old telephone service (POTS) is POTS. It won't affect your modem dialing, etc. God only knows why they would even send out such a notice, because other than your prefix probably changing, you probably won't notice anything different at all. gregicg@cadvision.com Greg Habstritt Intellitech Communications Inc. Calgary, Alberta, Canada ------------------------------ From: Mikeboyd@voyager.cris.com (Mike_Boyd) Subject: Re: What is DMS-100? Date: 21 Feb 1995 12:10:37 -0500 Organization: Concentric Research Corporation The DMS-100 is a central office switch manufactured by Northern Telecom. It should have absolutely no effect on standard consumer electronics connected to a standard telephone line. If you have any problems, contact PacBell and tell them to fix it. Central office equipment from any manufacturer is designed to be transparent to the end user. ------------------------------ From: hullp@COGSCI.Berkeley.EDU Subject: Re: Area Code/Prefix Trivia Date: 21 Feb 1995 06:27:21 GMT Organization: Institute of Cognitive Studies, U.C. Berkeley In article MSTRANDREW@aol.com writes: > The Point is in the United States because the portion is south of > the 49th. For many years, the local prefix 946 was assigned to the > 604 area code and local coin phones were desinged to accept Canadian > currency. Sometime in the early 1980s, the 946 prefix was reassigned > to the 206 area. I have not been there since, so I cannot offer an > update if the coin phones were transfered to accept US currency. A similar situation exists with Hyder, Alaska which is accessible by road only from BC, Canada. Phone service is provided by the BC phone company and is in the 604 area code, rather than in the 907 Alaska area code. Philip V. Hull INTERNET: hullp@cogsci.berkeley.edu BITNET: hullp@cogsci.berkeley.bitnet UUCP: ucbvax!cogsci!hullp OR: ucbvax!cogsci.berkeley.edu!hullp ------------------------------ Date: Tue, 22 Feb 95 12:59 CST From: dattier@wwa.com (David W. Tamkin) Subject: Re: Area Code/Prefix Trivia Organization: World-Wide Access, Vernon Hills, Illinois 60061-0285 The Moderator commented on : > Did you know it is impossible to travel from Point Roberts to anywhere > else in the United States by automobile without going through Canada? When a Nova Scotia native and I were looking at a map of Minnesota together, he pointed out that the Northwest Angle was cut across completely by Lake of the Woods, leaving part of it attached to Manitoba but separated from the rest of Minnesota. He said, "Look. There's a part of the United States where you have to go through Canada to get to the rest of the U.S., unless you fly or take a boat." I answered, "Yes. It's called Alaska." Point Roberts is not unique. I don't know whether telephones in the detached portion of Minnesota (occupied mostly by Northwest Angle State Forest and the Red Lake Reservation) are in area code 218 or 204. David W. Tamkin Box 3284 Skokie, Illinois 60076-6284 dattier@wwa.com MCI Mail: 426-1818 +1 312 714 5610 [TELECOM Digest Editor's Note: According to my Rand McNally state map of Minnesota, Northwest Angle *Provincial* Forest is located entirely within Manitoba. The small section of the Red Lake Indian Reservation (separated from the rest of the reservation, which occupies a huge chunk of northern Minnesota according to the map) is entirely in the USA. A small community up there is called Angle Inlet. The boundary seems to come down through the water in such a way that neighboring Bigsby Island, Big Island and Falcon Island are all in Ontario, Canada. A couple of small unnamed islands sit very close off the southern tip of Falcon Island, between it and Red Lake Indian Reservation which are barely inside the USA. Even though it appears to be in the USA, the only road shown on the map which leads from the provincial forest up to Angle Inlet is referred to as provincial highway 525, even within the USA part. Now if you look at a map of Manitoba or a map of western Ontario on those the boundary line is drawn so that a small portion of Falcon Island and Big Island are also part of the USA -- just the western and southernmost tips of each. I am amazed that David, who once took an entire evening driving me all over the northern boundary line between 312/708, carefully pointing out house by house, street by street and backyard by backyard where 312 ended and 708 began, as well as where Centel's territory started and Illinois Bell's ended does not know whether the phones at the Indian Reservation -- if there are any -- are serviced out of 218 or 204. Actually, I think they are serviced out of 807, and the central office in Kenora, Ontario which is the nearest town of any size. And what area code covers the largest geographical area? Probably 403 which is all of Alberta and the Yukon/Northwest Territories, although 907 in Alaska is also large. 808 has now become huge also since where it traditionally was only Hawaii in the past, now it also includes Midway Island, some distance away and the islands in the US Pacific Trust. Also, watch and see if 'country code 671' in Guam doesn't soon become 'area code 671' in the USA dialing plan. It is the one remaining place in the scattered possessions of the USA which still has to be dialed as an international point -- and although you young'uns wouldn't remember it, we used to have to call Hawaii through the operator as an international call also, *even after it became a state in the USA* for a few years until 808 was assigned. PAT] ------------------------------ End of TELECOM Digest V15 #112 ******************************