140 lines
7.3 KiB
Plaintext
140 lines
7.3 KiB
Plaintext
Regarding the file "24to96.zip", which "explains" how to increase the speed
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of a 2400 baud modem to 9600:
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THIS FILE IS EITHER A HOAX OR ABSOLUTELY THE WORST TECHNICAL DOCUMENT EVER
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WRITTEN. DON'T TRY IT!!!!!!
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In my opinion, it originated as a hoax, but since I know of two cases where
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it has resulted in the destruction of perfectly good 2400 bps modems, I
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thought I would write up this "rebuttal", and encourage all to ignore the
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24to96 file, as well as remove it from the BBS's it has shown up on.
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The problem with this type of "joke" is, unless the reader is fairly
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technical and knows something about chips and especially about modems, it
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almost sounds as though it would work! That has been true in the two cases
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I know of. The instructions sounded plausible to a couple of newcomers to
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electronics, and caused them to open up their modems, and when they found a
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slight match between their modems construction and the 24to96 instructions,
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they jumped in and hacked away. The fact that these files were retrieved
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from BBS's with solid reputations for policing the quality and authenticity
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of the files gave the experimenter's confidence they would not have felt had
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they retrieved the data from the National Enquirer! In addition, overly
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enthusiastic uploaders have added testimonials to the explanation of the file
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(maybe to enhance the joke?) such as "I've tried this and it really works!".
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If they have, they should contact me, and we will start up another company to
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build 9600 modems this new and revolutionary way which will surely blow all
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competitors away, since the chips listed are 1/6th the cost of the next
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cheapest 9600 bps chip set.
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Lest you wonder why I think I know so much about this, my credentials:
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degree: BS Electronics Engineering/Mathematics, AAA ranked University
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20+ years engineering experience
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7 years modem design experience
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have designed 40+ modems using the chips in the 24to96 file
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founder of three modem companies now in business
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[haven't bragged that much in 20 years!]
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Specific problems in "24to96" (other than horrible english and grammar):
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(1) The INTEL part numbers called out are not INTEL part numbers. They are
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probably manufacturer's part numbers for a particular Hayes clone modem, but,
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they could just as easily be spare tires for a volvo motorcycle!
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(2) The SC11005 chip called out in the instructions is also not an INTEL
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number; it is a SIERRA number. Specifically, it is a SIERRA V.22 bis modem
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filter (don't recall all the exact specs).
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(3) They instruct you to remove the SIERRA SC11005 chip and replace it with
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an SC11020. In the first place, the SC11020 is essentially a custom
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microprocessor (not a filter of any sort), in the second place, the SC11020
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has about twice as many pins as the SC11005! Not to mention it uses
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different power supply connections and voltages and may possible blow up if
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you could get it rigged in just right. An experienced technician would
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notice that right off, but again, some have just enough experience to feel
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they can do this, but do not realize what is going on until they have already
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hacked the SC11005 (or some other part) out of the modem (if they even FOUND
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one in the first place!).
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(4) To the best of my knowledge, there is no way to upgrade a V.22bis modem
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to any kind of 9600 bps modem no matter what you do. It is not a matter of
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"bandwidth".
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(5) I tried unsuccessfully for 4 years to buy chips from US Robotics. Why
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would they sell cheap upgrades instead of expensive HST modems?
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(6) "Optional Lap-M error correction".
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This is the only part of the instructions that won't hurt your modem,
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though it is definitely NOT V.42 anything. You may recognize this as the
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"noise filter" circuit explained in a number of BBS files over the past
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couple of years.
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Since Lap-M error correction is a SOFTWARE function, it goes without
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saying that you cannot add Lap-M error correction to a modem simply by adding
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a series RC network between tip and ring on the phone jack!
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To add Lap-M error correction requires the addition of software requiring
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thousands of man hours to write and debug, and a microprocessor capable of
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executing the software in real time. At 9600 bps this is no small
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requirement!
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(7) A 9600 bps modem requires support circuitry at least 10 times better
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(higher quality, lower distortion, better echo-canceling, etc.) than 2400 bps
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modems. Dropping a 9600 bps modem chip set into a 2400 design would barely
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function and would probably fail miserably in actual use, provided of course
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such a thing were even possible.
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**************************************************
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Now, if you had already figured out this file was a joke, Congratulations!
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You are officially designated a technical sophisticrat! But, remember, most
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modem users are not technical and will not be able to see through this as
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easily as you did. If two people who knew me and could call for help have
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ruined modems over this irresponsible document, how many others did also, and
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could not call for help? (BTW, another guy mentioned to me he was going to
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try it and I talked him out of it--that makes three I know of). This is a
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reckless joke, and I consider it a "HARDWARE VIRUS" document; those who
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originate and promote such things are no better than those who write and
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spread viruses.
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If you had not seen through this document, I am glad you took the time to
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download and read this. Please, NO MATTER HOW MUCH SENSE THIS ALL MAKES TO
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YOU, DO NOT TRY TO DISASSEMBLE AND UPGRADE YOUR MODEM USING THESE
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INSTRUCTIONS! In fact, even if you managed to add V.42bis to your modem
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somehow, unless you purchase a license from IBM, UniSys and British Telecom
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to use it, IT WOULD BE PIRATED SOFTWARE AND YOU WOULD BE A SOFTWARE PIRATE.
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V.42/bis is owned and licensed by IBM, UniSys and British Telecom; their
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license fees are substantial and are included in the cost of a V.42/bis
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capable modem.
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If you still want to try it, at least find a friend or solicit the help of a
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student or ??? They won't be able to do the upgrade either, but maybe THEY
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can convince you this is baloney!
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I don't usually "go public" this directly. When I first read this file I
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thought it was intended to be serious. When I read it again I knew it was
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obviously a joke. When people started taking it seriously and suffering from
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it I became angry. I ought to actually publish instructions for upgrading
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from 2400 bps to 9600 bps. I think it would parallel the recipe I once
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learned for cooking common lake Carp (a "trash" fish in the U.S.):
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Clean the Carp
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Lay it out flat on a redwood shingle
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Generously season with salt, pepper and dill
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Place in a 400 degree oven and cook for 3 hours
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To eat, throw away the carp and eat the shingle!
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The modem instructions would be:
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Remove all interior components from your 2400 bps modem
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Retain the case, power switch and lights
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Put the 9600 bps sub-section you purchased into the case
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Screw it down and connect up the switch and the lights
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Throw out the 2400 bps modem
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Well, that's about it. I've done my bit for the modem world, saved it from
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a terrible fate, right?
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Well, maybe not...............
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Larry Holmes
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