forrette@cory.berkeley.edu (Steve Forrette) (06/04/91)
In article <telecom11.389.6@eecs.nwu.edu> Jamie Mason writes: > Of course, now we have computer keyboards on fast computers > which will accept chracters faster than Superman could type. And my > local switch can handle my modem dialing with DTMF tones of less than > a 35ms duration. This reminds me of a "pet peeve" (sic?) that I have with the newer modems. Both the Hayes 9600 V-series and the $74 2400 card-modem I have won't accept an ATS11 value (DTMF duration) of less than 50ms. The default seems to be 100ms. The Hayes will take a smaller value, but use 50 during tone generation. The clone returns ERROR for a value less than 50. The old 1200 geniune Hayes that I have will take values down to 1ms, and actually do it as well. Since my switch will reliably take 36ms, I see no reason to not allow me to dial at that speed. Anybody (Toby?) know why the newer modems are handicapped/differently-abled in this manner? Steve Forrette, forrette@cory.berkeley.edu [Moderator's Note: And while Toby is answering that, here is another question: how come US Robotics has a condition you can set which allows for 'quick dialing', or dialing without waiting the obligitory two seconds before starting? Hayes used to claim (maybe still do) that telco tariffs require a two second pause before dialing. You could not set that particular S-register less than 2. Telebit seems to feel the same way ... but USR lets you go off hook and bang those digits right out if you set the register for it. PAT]
Jamie Mason <jmason2@utcs.utoronto.ca> (06/05/91)
In article <telecom11.423.13@eecs.nwu.edu> forrette@cory.berkeley.edu (Steve Forrette) writes: > This reminds me of a "pet peeve" (sic?) that I have with the newer > modems. Both the Hayes 9600 V-series and the $74 2400 card-modem I > have won't accept an ATS11 value (DTMF duration) of less than 50ms. > The default seems to be 100ms. The Hayes will take a smaller value, > but use 50 during tone generation. The clone returns ERROR for a > value less than 50. The old 1200 geniune Hayes that I have will take > values down to 1ms, and actually do it as well. The default on my modem (an old USRobotics "VARmodem" 2400 internal) for the tone generation is 70ms. 70ms is obnoxiously slow, as it is. *How* can they set their *fastest* speed to 50? I guess it is like those databases which try to get smart about names, and inevitably end up mangling esoteric names; you know a little more about your CO switch than the modem, but the modem won't give you the benefit of the doubt. My modem, like your old 1200, will go right down to 1ms, but the 1ms is a pretty feeble attempt at DTMF. > [Moderator's Note: And while Toby is answering that, here is another > question: how come US Robotics has a condition you can set which > allows for 'quick dialing', or dialing without waiting the obligitory > two seconds before starting? Hayes used to claim (maybe still do) > that telco tariffs require a two second pause before dialing. You > could not set that particular S-register less than 2. Telebit seems > to feel the same way ... but USR lets you go off hook and bang those > digits right out if you set the register for it. PAT] What S-Register is that? I know how to set my tone-generation rate really fast, but I don't see an S-register which controls how long my modem waits between taking the phone off the hook and dialing. My modem seems to wait for a dialtone before dialing. (Smart, eh?) As for the two second delay, while two seconds is a little long (restrictive) in the usual style of Phone Company tarrifs, *some* delay *is* required. Dialing on my phone, I have to wait about one second before I get the dial tone. I can't dial sooner, or it will miss some digits. Anyone know *why* 35ms (or 36ms) seems to be a universal limit on modern exchanges? Is this designed in? Also, I have heard of, but never heard officially, of a telco tariff which requires that autodialers not retry the same number more than ten0 times in a row automatically. This lead to: a) some crippled terminal programs which won't do more than ten retries before having to be restarted, and b) crippled hardware -- my DUoFone 195 (an old Radio Shack gadget) has an auto redialer which keeps trying till there's no more busy. But it will only try a maximum of ten times. Of course, this is all obsolete now, in the days of Call Return, where the Network does it for you. Jamie [Moderator's Note: Register S-6 in many modems sets the length of time to wait off hook before dialing. In the USR, the command ATX6 overrides the two second delay and dials immediatly. The ten attempt limit is to prevent repeated harassment of people who get wronh number calls intended for modems. Telco's repeat dialing feature won't change this; the modem does not care if it dials 7-D or *66. After ten tries, it will stop dialing. PAT]
"Marc T. Kaufman" <kaufman@neon.stanford.edu> (06/05/91)
> to feel the same way ... but USR lets you go off hook and bang those > digits right out if you set the register for it. PAT] The regulation in question is 68.314(a)(2), but it applies to answer, not originate: 68.314 Billing Protection (a) Call duration requirements on data equipment connected to the Public Switched Network, or to Tie Trunks, or to Private Lines that access the Public Switched Network. (2) Registered terminal Equipment Registered terminal equipment for data applications shall assure that, when an incoming telephone call is answered, the answering terminal equipment prevents both transmission and reception of data for at least two seconds after the answering terminal equipment transfers to the off-hook condition. Marc Kaufman (kaufman@Neon.stanford.edu)
Jamie Mason <jmason2@utcs.utoronto.ca> (06/06/91)
In article <telecom11.426.1@eecs.nwu.edu> the Moderator Notes: > [Moderator's Note: Register S-6 in many modems sets the length of time > to wait off hook before dialing. In the USR, the command ATX6 > overrides the two second delay and dials immediatly. The ten attempt Oops. I looked *right past* that in my modem manual. You are right: S6 (default) "Number of seconds modem waits before dialing." However, the modem does not dial immediately after picking up the phone -- it waits for a dial tone. And even X does it: "If set to X2, X4 or X6, modem ignores this regiser and dials as soon as it detects a dial tone." I don't find this unreasonable. The two second delay is to stop the equiptment from dialing before the CO switch is ready. If there is a dial tone (even before two seconds), then the switch is ready --- that is what the dial tone means. This takes about 1sec on my exchange. Of course I could set S6 to a lower value than two, but why bother when my modem can detect dial tone? > limit is to prevent repeated harassment of people who get wronh number > calls intended for modems. Telco's repeat dialing feature won't change > this; the modem does not care if it dials 7-D or *66. After ten tries, > it will stop dialing. PAT] *66 and *69 don't just call the appropriate number here. The call the number, then if it is busy, they 'camp on' in. That is to say, they switch calls *me* back to let me know that the number is free. When I pick up the phone, it calls the number automatically. So it does not have to try ten times -- just once. Then the network tries all by itself. That's why "this is obsolete". Jamie [Moderator's Note: Sure, and when the network connects, it will ring you back, and your modem will respomd in *answer mode* to the ringing phone. Or do you manually intercept it at that point and gie ATD to the modem to force it to go on line? PAT]
"76012,300 Brad Hicks" <76012.300@compuserve.com> (06/06/91)
> Also, I have heard of, but never heard officially, of a telco > tariff which requires that autodialers not retry the same number > more than ten times in a row automatically. Doubtless some legal type will look this up for us and cite the exact ruling, but it's not a tariff, it's a law. It was passed by Congress in the aftermath of that guy who got hacked off at one of the televangelists (I can't remember if it was Falwell, Roberts, or Robertson) and set up his modem to dial their fund-raising 800 number every minute or so for several weeks. Since they got charged $1 for every "completed" call, this guy ran up a bill on their nickle that reached into the tens of thousands of dollars. Since the guy left it going for a LONG time, it was trivial to trace the calls back to him. The "ministry" in question tried to bring phone harrassment charges against him, but due to a quirk in the law of the time, phone harrassment couldn't be brought in a case where the person charged never spoke into the phone, or some such triviality. That's when Congress got involved. (Televangelists + Congresscritters = Danger.) Some Congresscritter held hearings on the matter, which concluded that (a) what this guy had done was Bad and should be stopped, and (b) lots of other people were complaining about getting repeated redials from modems when BBS listings were wrong or out of date. Result was new legislation making it illegal to dial the same number more than ten times in a row. This may well be the most worthless piece of legislation short of National Rutabaga Day, since (a) the telcos don't enforce it in any way, so most modem users ignore it, and (b) it doesn't achieve the stated goal, since there's nothing that requires you to actually DO anything to confirm the phone number ... just dial "time and temp" once after every tenth try, and you're in the clear. So I guess it's just in there to have something to throw at guys like Perpetrator "A" above. Of course, this didn't rescue the televangelists, either. Did you hear about the 800 Club? In the aftermath of all of the above, a Minneapolitan (active in both gay rights and Pagan rights, among other political causes, and a member of the Minnesota Democratic Farm Labor Party) came up with the bright idea of putting together a single sheet with a list of the 800 numbers of all of the televangelists that she perceived were using tax-exempt donations to attack the civil rights of gays or Pagans, with instructions that all you had to do "join" the "800 Club" was to dial one of the phone numbers every day; preferably a different number each day. Minimum "compliance" was to get the person on the other end to answer; "bonus points" were allotted if you could draw them out into a conversation. (My favorite: Caller: "Excuse me, but what time is it?" Operator, startled, usually answers. Caller hangs up. Drove several operators crazy enough to quit, we heard.) At its peak three years ago or so, I heard an estimate that there were literally thousands of "members" of this club. The activist who started it claimed that during her calls, almost all of the ministries told her that because of those "awful gays and satanists" tying up the lines and adding so much to the phone bills, most of the ministries were going to have to give up fund-raising in this manner. And all as legal as church on Sunday -- to turn a phrase. - J. Brad Hicks [Please send direct responses to jbhicks@mcimail.com, not to the address above. Thank you!] [Moderators Note: All quite legal? Maybe ... all quite petty? A definite ten-four, good buddies ... People who hide behind a phone line to harass and play games do NOT get any sympathy from me, regardless of the validity of their cause otherwise. I have to wonder how (for example) {The Advocate} -- which advocated harassing Falwell in this way -- or the National Gay and Lesbian Task Force or other gay rights organizations would like seeing *their* 800 numbers polluted like this, giving them a multi-thousand dollar phone bill and forcing them to disconnect the number and preventing people who need to call them on that line from doing so? Actually, the guy in Georgia who did that to Falwell ran the bill up more than 'several thousand dollars'. It was about a hundred-thousand dollars, and Falwell's only loss was the time spemt by a dozen operators answering bogus calls once a minute and the time spent during one month by the Director of Telecom Services for Falwell's organization and the local telco in tracking down the problem. (At first they thought it was a failure in their own equipment (they take incoming calls through an ACD behind a centrex). AT&T (his 800 carrier) took a goodwill charge-off for the whole thing, and I think the originating telco agreed to accept a chargeback for some of what AT&T wrote off. So who lost money? Only us ratepayers, that's all. PAT]
"Cliff H. Wallach" <wallach@void.rtsg.mot.com> (06/06/91)
In article <telecom11.423.13@eecs.nwu.edu> is written: -X-Telecom-Digest: Volume 11, Issue 423, Message 13 of 13 > Since my switch will reliably take 36ms, I see no reason to not allow > me to dial at that speed. Anybody (Toby?) know why the newer modems > are handicapped/differently-abled in this manner? Some foreign administrations have laws about the minimum DTMF time. Modem chip vendors hardwire some limit so they can sell chips to multiple markets. US Robotics designs their own modem datapumps, so any DTMF time limit is governed by the supervisory software. We used the modems that we designed. > [Moderator's Note: And while Toby is answering that, here is another > question: how come US Robotics has a condition you can set which > allows for 'quick dialing', or dialing without waiting the obligitory > two seconds before starting? Hayes used to claim (maybe still do) > that telco tariffs require a two second pause before dialing. You > could not set that particular S-register less than 2. Telebit seems > to feel the same way ... but USR lets you go off hook and bang those > digits right out if you set the register for it. PAT] The fast dial mode checks for dial tone before dialing. I believe this is the only US telco requirement. USR has advertised fast dialing for seven years with any complaints. How many people will pick up a handset and start dialing without waiting two seconds? Cliff Wallach uunet!motcid!wallach
Peter Creath <peterc@sugar.neosoft.com> (06/06/91)
Telco's desire for a two-second delay is to give their equipment time to register your line and give you a dial tone. You forgot to mention that the only way a USR (at least that's what it says in MY manual) can skip the delay is to listen for the dial tone and begin dialing as soon (read about 1 or 2 ms) as it hears the dial tone. The difference between ATX5 and ATX6 is that X6 listens for dial tone and gives you the ability to speed dial.
Al L Varney <varney@ihlpf.att.com> (06/07/91)
In article <telecom11.426.1@eecs.nwu.edu> jmason2@utcs.utoronto.ca (Jamie Mason) writes: > Anyone know *why* 35ms (or 36ms) seems to be a universal limit > on modern exchanges? Is this designed in? Yup, designed in. In order to meet the goal of less than one occurrence of false digit simulation in 1500 calls from room noise, etc., the digit tones have to be present for a period of time with no other significant frequencies, except dial tone must be ignored. Thus the standard for requiring 40 msec. as a lower bound, for both the digits and the inter-digital interval. Switches should reject digits shorter than 23 msec., and since the loop can distort signals somewhat (Right, Toby?), the transmitter should use about 50 msec. Switches use 50 msec. when using DTMF to PBXes. Al Varney, AT&T Network Systems, Lisle, IL varney@ihlpf.att.com
Greg Andrews <gandrews@netcom.com> (06/07/91)
In article <telecom11.423.13@eecs.nwu.edu> forrette@cory.berkeley.edu (Steve Forrette) writes: > This reminds me of a "pet peeve" (sic?) that I have with the newer > modems. Both the Hayes 9600 V-series and the $74 2400 card-modem I > have won't accept an ATS11 value (DTMF duration) of less than 50ms. > The default seems to be 100ms. The Hayes will take a smaller value, > but use 50 during tone generation. The clone returns ERROR for a > value less than 50. The old 1200 geniune Hayes that I have will take > values down to 1ms, and actually do it as well. Hmmm. You want your modem to use 36 ms instead of 50? So exactly how much time would you save with that extra 14 ms? I note that the S11 register controls the duration AND spacing of the tones, so every tone would be 14 ms faster and the space in between would be 14 ms faster. Seven digit numbers would be seven multiplied by the S11 setting, multiplied by two: 555-1212 = 7 x 50 ms x 2 = 0.7 seconds to dial the number 555-1212 = 7 x 36 ms x 2 = 0.5 seconds to dial the number A savings of 0.2 seconds Eleven digit numbers (ten digit with a leading 1 or 0): 1-408-555-1212 = 11 x 50 ms x 2 = 1.1 seconds to dial 1-408-555-1212 = 11 x 36 ms x 2 = 0.8 seconds to dial A savings of 0.3 seconds So for every eleven digits that the modem dials, the user can save 1/3 of a second if the modem uses 36 ms tones instead of 50 ms tones. How many switches in this country (and the world) can reliably handle DTMF tones faster than 50 ms? How many can handle them even that fast? Should modem manufacturers take steps to ensure their equipment works reliably with the broad range of switches out in the field, even at the expense of 0.2 - 0.3 seconds per call? Are modem users such speed demons that 0.3 seconds is begrudged? In my humble opinion, it's a little silly to get upset over such a small amount of time. Of course, I happen to work for Telebit technical support, so that may explain my viewpoint a little bit... Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | Internet: gandrews@netcom.COM
Dave Levenson <dave@westmark.westmark.com> (06/08/91)
In article <telecom11.423.13@eecs.nwu.edu>, forrette@cory.berkeley.edu (Steve Forrette) writes: > Since my switch will reliably take 36ms, I see no reason to not allow > me to dial at that speed. Anybody (Toby?) know why the newer modems > are handicapped/differently-abled in this manner? The noise picked up by a telephone mic, including some human voices, may contain brief bursts of energy that may be mistaken for touch tone signaling. Many touch tone signaling receivers are designed to reject tone signals shorter than 50 msec in an attempt to reduce their sensitivity to these false signals. Perhaps the modem makers are trying to prevent you from mis-dialing when using one of these switches. In article <telecom11.426.1@eecs.nwu.edu>, jmason2@utcs.utoronto.ca (Jamie Mason) writes: > Also, I have heard of, but never heard officially, of a telco > tariff which requires that autodialers not retry the same number more > than ten times in a row automatically. This lead to: a) some > crippled terminal programs which won't do more than ten retries before > having to be restarted, and b) crippled hardware -- my DUoFone 195 (an > old Radio Shack gadget) has an auto redialer which keeps trying till > there's no more busy. But it will only try a maximum of ten times. > Of course, this is all obsolete now, in the days of Call Return, where > the Network does it for you. The reason they don't allow an autodialer to dial too many times or too rapidly is to prevent 'gridlock' in the network. If a bunch of people with auto-redial equipment are rapidly redialing each other and getting busy signals because the called party is also busy redialing, the network tends to block, and all with non-revenue calls! If your auto-redial equipment backs off a bit, it lets some of those calls reach you. Call*Return does not do its work by continually redialing, but by queueing a request in a database common to your switch and the called switch. This does not result in network blockage from busy attempts, as CPE rapid-dialing does. Dave Levenson Internet: dave@westmark.com Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail: !westmark!dave Voice: 908 647 0900 Fax: 908 647 6857
Steve Forrette <forrette@cory.berkeley.edu> (06/09/91)
In article <telecom11.432.4@eecs.nwu.edu> Greg Andrews writes: > In article <telecom11.423.13@eecs.nwu.edu> forrette@cory.berkeley.edu > (Steve Forrette) writes: >> This reminds me of a "pet peeve" (sic?) that I have with the newer >> modems. Both the Hayes 9600 V-series and the $74 2400 card-modem I >> have won't accept an ATS11 value (DTMF duration) of less than 50ms. > Hmmm. You want your modem to use 36 ms instead of 50? [stuff deleted] > How many switches in this country (and the world) can reliably handle > DTMF tones faster than 50 ms? How many can handle them even that > fast? The point is not how many switches can handle what, but what MY switch can handle. I believe that the telco published minimum (i.e. what they guarantee) is 50ms, so the 100ms default of the modem is plenty to allow for customers to not have problems. By changing the default, I am telling the modem that I don't want the default used, but want my own value used instead. > In my humble opinion, it's a little silly to get upset over such a > small amount of time. Of course, I happen to work for Telebit > technical support, so that may explain my viewpoint a little bit... Greg, I think that I can live with the .2 seconds extra. The point is that this attitude on the part of the manufacturer is all too common in the telecom industry today. It's this attitude that causes the Bay Area cellular carriers to require a "1" before dialing a long distance number, and not allowing the area code for local numbers. Just like the 36ms dialing, both of these once worked just fine, but now have been changed. Since all of these worked just fine at one time, there's no technical reason not to allow them. The attitude of "Sir, why do you need this?" gets really old after awhile. What good reason can you give for making these changes? It doesn't improve the service for those that follow the instructions and use the defaults, but makes things more difficult and annoying for those that know a little more and like to use the more obscure features. Here's another example: I recently ordered new phone service from Pacific Bell because of a move. I wanted a line with regular call waiting and busy transfer to my other number. I was told by the Business Office that this combination was not tariffed, and was even read a quote from the Handbook stating that call waiting cannot be on a line with either busy or no-answer transfer. I had exactly that setup a couple of years ago from US West in Seattle. Call waiting kicked in first, then a third call would busy transfer to the other number. And if I was dialing out on the modem and invoked cancel call waiting, the first incoming call would busy transfer. Is someone going to tell me that US West's 1AESS's and DMS-100's can to this, but Pacific Bell's cannot? Of course they can. But somebody decided "Nobody will need this, and it may be confusing anyway." So, I could not purchase this no matter how well I understood it. I was willing to pay for all these features, but they wouldn't take my money because somebody decided that this isn't what I really needed, and/or that I wouldn't understand it. I complained, and tracked somebody down in the department that makes the marketing decisions for Custom Calling features. First they tried to give me the line that it was not technically possible. Once that was dismissed, the complication and lack of need was brought up. Do you see the danger of this attitude? In article <telecom11.432.6@eecs.nwu.edu> Dave Levenson writes: > Call*Return does not do its work by continually redialing, but by > queueing a request in a database common to your switch and the called > switch. This does not result in network blockage from busy attempts, > as CPE rapid-dialing does. Oh, but it does! When queueing a call, the calling switch sends a request every so often (around 30 to 45 seconds) over the SS7 network to the destination switch, asking it if the destination line is idle. If it is, then the caller is rung, and upon answer, a "fresh" call attempt is made (which could reach busy if the destination started another call in the meantime). It does NOT work by queueing a request at the destination switch. Why this is, I don't know. I've read several journal articles about SS7 and the implementation of the CLASS features, and they never mentioned the rationale behind this, but did clearly explain that this is the way it works. Steve Forrette, forrette@cory.berkeley.edu [Moderator's Note: A funny story about automatic redial here in Chicago: I used my phone to dial my own number, and of course I got a busy signal, not a call-waiting tone. I disconnected and dialed *66. The recording told me the number I had dialed was busy, but that it if became free in the next thirty minutes, I would be called back 'with a special ring'. Well of course a few seconds after disconnecting a second time, my line was observed to be 'free', so I got the special ring (two short and one long). When I answered, after a couple seconds of silence the recording advised me 'the number you are calling was free, but it has become busy again ... we will continue trying.' I hang up, a few seconds later I get the special ring, and the same routine. Apparently this would have gone on for some time -- 30 minutes probably, since that is the time limit it originally said it would use to try and get through -- but I dialed *86 and 'cancelled my repeat dialing and automatic callback requests.' :) PAT]
Jim Gottlieb <jimmy@denwa.info.com> (06/09/91)
In article <telecom11.432.2@eecs.nwu.edu> 76012.300@compuserve.com (76012,300 Brad Hicks) writes: >> Also, I have heard of, but never heard officially, of a telco >> tariff which requires that autodialers not retry the same number >> more than ten times in a row automatically. > it's a law. It was passed by Congress in the aftermath of that > guy who got hacked off at one of the televangelists ... First off, I believe the limit is 16 retries. And I'm pretty sure the law was passed because of what happened when Bruce Springsteen tickets went on sale in D.C. and the network came to a standstill due to the number of people trying to call the ticket vendor. The real solution would have been to put such numbers on a high-volume prefix, or as they do here in L.A., the number to Ticketron is a special case in all local switches and tandems. But it being D.C., our lawmakers thought they had to pass a law. Never mind that I doubt that autodialers were a significant portion of the traffic that day. Most autodialers try only once every thirty or sixty seconds. More probable were people doing multiple manual repeat dials. If I press the Last-Number-Dialed button 17 times, do I go to jail :-) ?
Brent Chapman <brent@america.telebit.com> (06/10/91)
peterc@sugar.neosoft.com (Peter Creath) writes: > Telco's desire for a two-second delay is to give their equipment time > to register your line and give you a dial tone. You forgot to mention > that the only way a USR (at least that's what it says in MY manual) > can skip the delay is to listen for the dial tone and begin dialing as > soon (read about 1 or 2 ms) as it hears the dial tone. The difference > between ATX5 and ATX6 is that X6 listens for dial tone and gives you > the ability to speed dial. I used to have one of these modems (a USR 2400e). The problem I had was, in the exchange I was in (415-655; Oakland, CA), the switch apparently was NOT actually ready to accept digits as soon as it started generating dialtone. The modem would usually fail to complete calls when in the "dial as soon as you hear dialtone" mode; I'd hear the first burp of dialtone, then the modem tones, then nothing ... my assumption was that the switch was missing the first digit or two. Brent Chapman Telebit Corporation Sun Network Specialist 1315 Chesapeake Terrace brent@telebit.com Sunnyvale, CA 94089 Phone: 408/745-3264