Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site im4u.UUCP Path: utzoo!watmath!clyde!cbosgd!gatech!ut-sally!im4u!jsq From: jsq@im4u.UUCP (John Quarterman) Newsgroups: net.periphs,net.news,net.lan Subject: Re: 2400 (or higher) baud modems (4 of 4) Message-ID: <670@im4u.UUCP> Date: Sun, 24-Nov-85 15:24:22 EST Article-I.D.: im4u.670 Posted: Sun Nov 24 15:24:22 1985 Date-Received: Thu, 5-Dec-85 04:24:44 EST References: <632@im4u.UUCP> <667@im4u.UUCP> <668@im4u.UUCP> <669@im4u.UUCP> Reply-To: jsq@im4u.UUCP (John Quarterman) Organization: U. Texas CS Dept., Austin, Texas Lines: 557 Keywords: Hayes, Multi-Tech, Racal Vadic, Penril, ATTIS, Concord, CTS, etc. Xref: watmath net.periphs:921 net.news:4462 net.lan:1177 Summary: More modems; more explanations of CCITT V.22 bis. Here's what's left. Be sure to notice the date on each message before depending on it for ordering information. Some of these are a year old. One is the oft-quoted survey of December 1984 from Bruce Factor. It's reposted here in the interests of reducing the number of times it gets mailed around from person to person. Not to mention historical interest: prices on 2400 baud modems have dropped by half within a year. >From ut-sally!topaz!packard!cbosgd!ukma!david Mon Nov 18 13:35:09 1985 Date: Sat, 16 Nov 85 10:48:17 est From: ut-sally!topaz!packard!ukma!david (David Herron, NPR Lover) Subject: Re: 2400 (or higher) baud modems To: im4u!jsq Newsgroups: net.periphs,net.news,net.lan, The following are messages I've been collecting about 2400 baud modems. We have 4 Multi-Tech 2224's here. They were selected by the person we feed in Cincinnati after he looked at all the modems he coiuld get his hands on. These modems do NO error correction protocols, which was a conscious decision because he was having terrible problems with the ones that did do error correction. Date: 20 Dec 1984 06:52 MST (Thu) >From: Keith Petersen To: Info-Cpm@AMSAA, Telecom@MIT-MC Subject: 2400 baud modems This is file 2400BAUD.TXT - relayed from the RCPM circuit: --Keith >From: Wayne Masters, Potpourri sysop (408) 378-7474 300/1200/2400 baud San Jose, Ca. Subject: New 2400 baud modems 8/19/84 Many of you have asked technical questions about the 2400 baud modems now on the market (and more being introduced monthly). As most of you know by now Irv Hoff and I have been beta testing 2400 baud for several months. The test results are amazing to say the least. Running controlled tests on standard dial-up phone lines with random "noisy connections", the number of "hits" on a given file transfer is less by a factor of 10 using 2400 baud vs 1200 baud. So it is concluded that 2400 baud technology is working and will soon be available on most commercial and private dial-up systems. Now, what is a "standard" 2400 baud modem? You will no doubt see various technical descriptions of a given 2400 baud modem touting it's features. Be sure the modem you choose has this specification: CCITT recommendation for a V.22 bis modem communicating at 2400 bps. Further explanation of this CCITT standard: Frequency- Bell 212A Encoding modulation- 16 level psk (quadrature AM or QAM) This sounds a lot like the Bell 212A standard for 1200 baud--and it is. The difference is in the encoding or modulation scheme. Bell 212A 1200 baud uses 4 level psk and 2400 baud uses 16 level psk. If you "listen" to the 2400 baud carrier it will sound exactly like the familiar 1200/212A- like "static" or a scratchy noise. Features to look for in your search for the "right" 2400 baud modem: 1. Does it retain 300 baud bell 103 capability? (most offer 1200 baud as a "fallback") 2. Is it "smart"--a biggy if you intend to call other systems a lot. 3. Does it offer autoanswer--a biggy if you run a remote system. 4. Price--a real biggy So far, none of the modems on the market offer all these features in a "standalone" modem. That is one big reason why Irv Hoff and I have been involved with Racal-Vadic--not only beta testing to prove 2400 baud technology...but to get the features most users prefer designed into the modem. Others may follow some day but Racal Vadic will introduce their "standalone" modem in time for Christmas 84 with the following features: 1. Smart-autodialing. It will recognize both the Hayes and Vadic commands. 2. 0-300 baud at both Bell 103 and Vadic protocols 3. 1200 baud at both Bell 212A and Vadic protocols 4. 2400 baud CCITT V.22 bis 5. Price is expected to be $695.00 retail The first release will be an external RS-232 model. Early 1985 will see the single card slot version for IBM PC's and compatiables. In order for 2400 baud to be in "great demand" there must be systems available for the users to access. I am working with Racal-Vadic to identify RCP/M and RBBS systems where 2400 baud modems could be placed to generate public interest in 2400 baud. Sysop's should contact Potpourri at 408-378-7474 if interested in participating. Now about software to support 2400 baud. Both MDM7 and MEX will support 2400 baud if the user modifies his port overlay to setup his port for 2400 baud. For sysops who use BYE3, the problem is different. Most implementations of BYE rely on the hardware's Data Available signal (DAV) to trigger a check-for-carriage-return sequence at different baud rates. If most hardware is like mine (Z80 SIO), if the hardware is set to look at 300 baud and the modem answers at 2400 baud the DAV is never set and you are in an endless loop. Same thing happens if you set the hardware to 2400 and the modem answers at 300. I modified BYE3 (version 26 and up) to handle TSTBAUD differently. I chose to look at each baud rate in 2 second windows, 300 first, then 1200 and 2400, and loop thru this sequence until a C/R or L/F is detected. The caller is never more than 4 seconds away from his calling speed but must continue to issue c/r's until the familiar message "Nulls, if needed" is displayed. Sysop's who choose to use BYE3 need only add the "SET2400" code into their port insert. Well, enough for now. Feel free to contact me if you are more confused now than you were before reading this. -wayne masters, Potpourri sysop- 408-378-7474 ------------------------------ End of TELECOM Digest ****************************** Path: ukma!qusavx!hasmed!cbosgd!ihnp4!houxm!whuxlm!harpo!decvax!genrad!mit-eddie!godot!harvard!seismo!brl-tgr!tgr!philabs!sbcs!bruce%cmcl2.uucp@Seismo.ARPA >From: bruce%cmcl2.uucp@Seismo.ARPA Newsgroups: net.micro.cpm Subject: 2400 baud modems Date: Thu, 27-Dec-84 09:16:05 EST For those of you in the market to buy 2400 baud modems I want to inform you of a great deal. I would like to state that I am not affiliated with ANY of these companies, and I am not receiving and benefits by posting this information! After spending a few days pricing modems I have compiled the following information (saving the best for last). If anyone has any additional information I would greatly appreciate it. We were interested in rack mounting them so most of the prices given are for cards that would plug into a rack. "box" refers to a stand alone modem. DEC 1 - (800) 962 - 3244 now DF112-AM 300/1200 card $ 506 now DF126-AM 2400 only card $ 634 Racal Vadic 1 - (800) 482 - 3427 now VA212PAR 300/1200 card $ 445 3/85 VA4224 1200/2400 card $ 740 now VA1681 houses 16 rack $ not priced yet Concord Data Systems (617) 890 - 1394 Q10-24 now CDS224 AA/ORG 1200/2400 box/card$ 845 $ 825 now CDS224 Autodial 1200/2400 " $ 995 $ 975 now CDS224 ARQ 1200/2400 " $1295 now CDS224 ARQ Auto 1200/2400 " $1395 now CDS224 Super 1200/2400 " $1695 now CDSRM-07A houses 7 rack $ 750 Hayes 1 - (800) 241 - 6492 now Hayes1200 300/1200 box/card$ 499 2/85 Hayes2400 300/1200/2400 box/card$ none now 08-00056 houses 6 rack $ 766 Quantity Discounts are minimal. Micom 1 - (800) 527 - 0204 Q >16 now M3012 300/1200 box $ 495 now M3012 plus 300/1200 box $ 595 1/85 M3024 1200/2400 box $ 795 1/85 M3024 plus 1200/2400 box $ 895 $ 805 " " " card $ 845 $ 760 now M3200 houses 16 rack $ 750 General Datacomm (203) 574 - 1118 Q 10 - 19 now DC211AL 300/1200 box $ 675 $ 595 " " " card $ 585 $ 520 1/85 DC2412 1200/2400 box $1195 $1050 " " " card $1105 $ 790 " DS1 houses 16 rack $ 795 Paradyne 1 - (800) 482 - 3333 or 1 - (800) 342 - 3532 now DTU1200D 300/1200 $ now 1200/2400 $ 900 NEC 1 - (800) 538 - 8166 Q 11 -20 now N212BRL 300/1200 box $ 795 $ 669 " " " card $ 725 $ 606 " DSP2430 1200/2400 box $1095 $ 976 " " " card $ 965 $ 855 " N4083 houses 8 - 1200 rack $ 625 " SR0801 houses 8 - 2400 rack $ 900 QUADRAM (404) 923 - 6666 Q > 3 now QM10000 300/1200 $ 695 $ 625 not available ?/2400 $ NO Rack mounting. Ven-Tel 1 - (800) 538 - 5121 Will Call me back. 300/1200 $ ?/2400 $ Promethus (415) 490 - 2370 (check 800) Distributor: Will call me back. 300/1200 $ ?/2400 $ Fujitsu (408) 946 - 8777 ext 576 not available 300/1200 $ now F1935B 1200/2400 $ 895 ------------------------------- CTS Datacomm (203) 743 - 3681 Pete Coccaro Distributor: Professional Network Services Harvey Schlesinger (617) 449 - 6460 Model: CTS2424AD These people had by far the best deal. The list price for the Stand Alone (box) modem is $ 795 The list price for the (rack) mounted modem is ~$ 700. Besides starting off $ 200 less than everyone else their quantity discounts are very good. The Stand Alone modem will be available starting January, and their rack mount modem should be available February. Here is a Quantity discount price list. Quantity %dicount S.A. rack ======== ======== ==== ==== 1 list $795 $700 2-5 10 % 716 630 6-10 20 % 636 560 11-25 25 % 596 525 25- 30 % 556 490 For all of you usenet sites that are still running 1200 (or possibly even 300) the modems will pay for themselves very quickly. >From all of the literature that I have recieved here are a few of the advantages of this modem above the others: 1) works at 300 or 1200 or 2400 asyn (others only 1200/2400) 1200 or 2400 sync 2) Stores 10 numbers (40 chars each) (others only 1) 3) For tone dialing it dials ALL 12 (others only can generate tones including (* and #) numbers 0-9) This last one caused a nasty problem when we needed to generate the extra tones because some of the sites we talk to have switching systems that require them (Gandalf). 4) Will automatically change the speed (some of the others needed to the other modem. a manual intervention). --------------- usenet: {philabs, allegra}!sbcs!bruce Bruce Factor Path: ukma!qusavx!hasmed!cbosgd!ihnp4!houxm!vax135!ariel!mdg >From: mdg@ariel.UUCP (M.GALE) Newsgroups: net.micro.cpm Subject: Re: 2400 baud modems Date: Fri, 28-Dec-84 09:20:51 EST Please note at the beginning that this is coming from an account on an AT&T computer. Just wanted to point out that in the recent summeries of modems available people seem to be missing a major manufacturer of modems -- A T & T. Check it out with an A T & T - I S sales rep. They've got 1200/2400 standalone and rackmount systems. And you don't call it the Bell 212 standard for nothing. Please note that I do not work in that department and know only the basics concerning such hardware i.e. it exists. I am not an employee nor an authorized representative of any part of AT&T, I only help solve problems for them on a contract basis. To think that my opinions are those of the company is ludicrous. Michael D. Gale "I just like blinking lights-the DECsystem 10 operator's panel is a work of art" blink-blink-blink-burnout-blink >From rjk@mgweed.UUCP (Randy King) Sun Feb 6 01:28:16 206 Path: ukma!cbosgd!ihnp4!mgnetp!mgweed!rjk Newsgroups: att.general,net.unix Subject: Framing errors and autobaud @ 2400 It seems that autobauding from 1200 down to 300 by means of a framing error is quite reliable when the 300-baud user types almost any character. Hence for years uucp info has contained strings like: login:--login: where the "--" implied "send CR". The reverse did not work, so the 1200-baud user would send a BREAK to upshift the remote to 1200; hence login:-BREAK-login: for the uucp info. Now I am finding that downshifting from 2400 baud to 1200 baud more closely resembles the 300->1200 upshift in that sending a BREAK is the more reliable way. It is not always the case, however. There are times when just a CR from my 1200 baud modem calling a tri-speed modem at 2400 baud will cause the port to fallback to 1200. Many times, however, a BREAK is required to cause the downshift. If you have had experience with 2400 baud autobauding, including upshifts and downshifts among the speeds from 110->2400, I'd like to hear about your findings. This would be important information for future releases of UUCP information from sites with >1200 baud modems. Randy King AT&T-CP@MG ihnp4!mogul!rjk >From W8SDZ@SIMTEL20.ARPA (Keith Petersen) Sun Feb 6 01:28:16 206 Path: ukma!cbosgd!ihnp4!houxm!whuxl!whuxlm!harpo!decvax!genrad!panda!talcott!harvard!seismo!brl-tgr!tgr!W8SDZ@SIMTEL20.ARPA Newsgroups: net.micro Subject: 2400 baud modem review Date: Sun, 31-Mar-85 10:40:40 EST The following review was not written by me. It was downloaded from a Remote CP/M system. Unfortunately there is no way to reach the author because it is unsigned. It is presented here for its possible informational value. Please address discussions/comments to the mailing list, not me. I don't own a 2400 baud modem. --Keith 10 Mar 85 *** DISCLAIMER *** The products described here were repeatedly tested for a specific application only. No value was placed on advanced features not directly related to their intended use. The opinion expressed herein is that of the reviewer and may, in fact WILL differ considerably from other reviewers' opinions. This is an unsolicited review. Anyone able to disprove the reviewes claims is welcome to do so. This review is about as unobjective as it can get. In a data processing environment, chances are the employee with a terminal and a modem (or computer) and access to the business computer via dialup will be more productive and is more likely to put in a few hours' worth of unsolicited overtime per week than the employee who has access to the same computer only during working hours. Therefore, it was decided that the office computer be set up with at least one high-speed dialup line and the most economical choice was that of a 1200/2400 baud modem. The modems were going to be used for two purposes: 1. unattended autoanswer 2. occasional use for dialout Testing was started as soon as modems became available through a local distributor. Due to this factor only two brands were evaluated. Here is the story on both of them: 1. PENRIL 2024 The Penril 2024 seems to be the first widely available 1200/2400 baud modem, with the exception of the prohibitively priced VADIC 4400 series. The 2024's list price is somewhere around $900. The 2024 offers two baud rates, 1200 and 2400. The 1200 baud protocol can be switched from 212A to V.22 at configuration time. By today's standards, the 2024 cannot be considered a "smart" modem in that its smartness is limited to the ability to dial a phone number. Placing the modem in autoanswer mode is accomplished by simply configuring the internal and external switches according to the manual, releasing all front panel switches and plugging it in. The 2024 does not have a power switch (a definite plus in this application). Originating a phone call with the 2024 is a cumbersome procedure, especially in an application where the modem may be 100 feet away from the terminal. First, the modem must be taken out of autoanswer mode by pressing a front panel switch. Next, the originate baud rate must be selected by locking the HI/LO switch IN or OUT. Note that if you set up the modem for 2400 baud, you can call a 1200 baud number because of the "fallback" feature. You just have to adjust your terminal baud rate after connect. The 2024 has no abort provisions. While dialing, the TALK/DATA switch can be used to abort. When connected, you must either cause the remote computer to drop carrier or you again have to hit the switch. An alternative is dropping the DTR line low, but in some instances that's a bit hard to do. Dialing a phone number is very awkward. The sequence is "CRNnnnnnnn" so to dial 555-1212, you type CRN5551212^M^J. Fine if the ENTER key on your keyboard generates a CR-LF sequence; with most terminals you have to hit two keys. Sorry, no redial capability. The Penril worked fine calling the local TYMNET 2400 baud access number, but no connection was established to any long distance modem at 2400 baud. The modem is superbly suited for unattended autoanswer mode. the 2024 can be turned on and left alone and if something goes wrong it's the software but not the modem. The continuous high-pitched noise coming out of the built-in speaker may be objectionable to some -- it picks up the strongest local AM radio station. the speaker can be turned low or off via an internal jumper block. One 2024 modem was tested initially in early November 1984, and two were again tested in late February 1985. No difference was found between the three modems, even though the early onemay have been a preproduction unit. >From neuro1!sob@rice.ARPA Sun Nov 17 03:22:35 1985 From: Stan Barber Subject: modems Thought this might be of interest -------- begin included text ---------- Path: neuro1!shell!ut-ngp!ut-sally!seismo!lll-crg!dual!ames!jaw From: jaw@ames.UUCP (James A. Woods) Newsgroups: net.dcom Subject: Paul Baran, modem hero Date: 26 Jul 85 00:55:36 GMT # fools speed ahead that amazing telebit/dca 10kbit modem sure seemed like a minor miracle (infoworld, 7/22), so i called telebit for the technical dope. if the literature is to be believed, bad lines don't really faze the thing. i'm sure a few usenet sites with $2300 would jump for it. is it time to ring the death knell for CCITT modems, which, because of noise and gross fallback strategies, never reach their max throughput? hmm ... "packetized ensemble coding...inventor lists airport metal detector, invention of packet switching in 1964, and co-founding of equatorial communications (your friendly neighborhood spread spectrum service) among his credits". no slouch here. dca stock (telebit is private, but marketer dca is public) has risen to around $30 of late, from about $22 a few weeks back. oh, the dope -- - 512 carrier freqs. each modulated with either 6-bit or 4-bit QAM, or 2-bit QPSK, depending on SNR. - adaptive duplexing, to take advantage of the one-way burst nature of most traffic. - fallback in decrements of < 100 bps. (successive rate halving of the v22 standard is the real killer on dialups.) - bell 103, 212a, and hayes command language compatibility - call (800) telebit ames!jaw Path: neuro1!shell!ut-ngp!ut-sally!seismo!harvard!talcott!panda!genrad!decvax!decwrl!dec-rhea!dec-beta!dieter >From: dieter@beta.DEC Newsgroups: net.dcom Subject: Info on DEC DF224 \"Scholar\" Date: 30 Jul 85 18:52:17 GMT 2400 bps modems - reply >I was wondering about the compatibility of 2400 baud modems. > >ie: > >1) What different types of protocols are there, or aren't there? >2) Specifically, we have a bunch of ATTIS and Concords, which > are compatible, but how compatable are they with DECS new > DF-224s? >3) Which ones perform well, and which ones don't. >4) Is there a prevailing standard, or does it look like there > is going to be one. 1. Most modem vendors offer their own autodial protocol. Lately many have been implementing the Hayes protocol also, in one of two ways. One way is to offer two models, one with Hayes and one with their own. The other is to put the choice in the modem(Penril does this). At Interface many vendors criticized the Hayes protocol but sheepishly admitted that the marketplace demanded it. The DF224 does not support the Hayes protocol, it is unique like the ATTIS and some others. 2. The DF224 was tested with the CDS, Hayes, and Vadic it should be compatible with any other V.22bis modem - especially if it uses the Rockwell chip set (most of the market). 3. Of course the DF224 (Scholar) performs the best! What else could I say... Actually most of the V.22bis modems will be very similar, and we would expect all of the modems made with the Rockwell chips to work the same. 4. I presume the standard referred to is the Autodial method. The perception is that the Hayes autocall method is the most widespread...don't know if its true but it perceived to be so. Mostly due to Smartcomm software making life easy for PC users. The DF224 autocall method is very easy to use and the modem has an extensive menu, 15 stored numbers, redial, nametag calling, etc. I notice that the Hayes 1200 and 2400 versions are different, I wonder how much pain that has caused users wanting to upgrade. The initial question was about compatibility, I think you will find most of the recent V.22bis modems will be very similar. Most will also implement the fall back mode to be Bell 212A compatible rather than V.22. Those that adaptively equalize to the line in 1200 mode will work where a 212 will not. Ralph Dieter DEC Merrimack, NH -- John Quarterman, UUCP: {ihnp4,seismo,harvard,gatech}!ut-sally!im4u!jsq ARPA Internet and CSNET: jsq@im4u.UTEXAS.EDU, formerly jsq@im4u.ARPA