jparnas@Larouch Headquarters.UUCP (Jacob Parnas) (10/08/90)
I heard that there is a proposal for a extension to V.32bis that will have throughputs of 19200 baud without compression and up to 76800 with compression. Does anyone have any more information about this proposal? Thanks, ------------------------------------------------------------------------------ | Jacob M. Parnas | DISCLAIMER: The above message is from | | IBM Thomas J. Watson Research Ctr. | me and is not from my employer. IBM | | Arpanet: jparnas@ibm.com | might completely disagree with me. | | Bitnet: jparnas@yktvmx.bitnet \---------------------------------------| | Home: ..!uunet!bywater!acheron!larouch!jparnas | Phone: (914) 945-1635 | ------------------------------------------------------------------------------
casey@gauss.llnl.gov (Casey Leedom) (10/08/90)
/ From: jparnas@Larouch Headquarters.UUCP (Jacob Parnas) | | I heard that there is a proposal for a extension to V.32bis that will | have throughputs of 19200 baud without compression and up to 76800 with \ compression. Does anyone have any more information about this proposal? To be honest I doubt that your information is correct, but nevertheless, even at the known V.32bis/V.42bis expected speeds (57.6Kbps max (38.4Kbps ave?)) modem manufactures and others are going to have to beef up both their CPUs and serial chips. At some point it's going to be ridiculous to keep on trying to use EIA232 and we'll have to start using something else. Maybe even Ethernet as some have suggested ... :-) Casey
paul@actrix.co.nz (Paul Gillingwater) (10/09/90)
In article <69427@lll-winken.LLNL.GOV> casey@gauss.llnl.gov (Casey Leedom) writes: > To be honest I doubt that your information is correct, but > nevertheless, even at the known V.32bis/V.42bis expected speeds (57.6Kbps > max (38.4Kbps ave?)) modem manufactures and others are going to have to > beef up both their CPUs and serial chips. At some point it's going to be > ridiculous to keep on trying to use EIA232 and we'll have to start using > something else. Maybe even Ethernet as some have suggested ... :-) Hmmm.... don't look now... but I heard a rumour that Telebit have a hot new product ready to be announced at Interop next week! No doubt some kind soul will post more info as it comes to hand... -- Paul Gillingwater, paul@actrix.co.nz
tnixon@hayes.uucp (Toby Nixon) (10/09/90)
In article <69427@lll-winken.LLNL.GOV>, casey@gauss.llnl.gov (Casey Leedom) writes: > / From: jparnas@Larouch Headquarters.UUCP (Jacob Parnas) > | > | I heard that there is a proposal for a extension to V.32bis that will > | have throughputs of 19200 baud without compression and up to 76800 with > \ compression. Does anyone have any more information about this proposal? > > To be honest I doubt that your information is correct... Sorry, but I must have missed Jacob's original message. He is, in fact, correct -- CCITT Study Group XVII has indeed initiated a project to define the "ultimate modem" -- one that will operate full duplex on dial-up telephone lines at rates exceeding 14,400bps. The proposals so far call for operation at 19,200 or above, with some of the proposals talking about 24,000bps -- and this is WITHOUT COMPRESSION (i.e., a synchronous host would be able to acheive these speeds, full-duplex). Telebit's multicarrier modulation is a contender, but they have yet to demonstrate that they can do a multicarrier echo canceller so it will run full-duplex; other old-line modem companies with big research budgets, like Codex and General Datacom and Racal-Milgo will likely lead this project. -- Toby ----------------------------------------------------------------------------- Toby Nixon, Principal Engineer Fax: +1-404-441-1213 AT&T: !tnixon Hayes Microcomputer Products Inc. Voice: +1-404-449-8791 CIS: 70271,404 Norcross, Georgia, USA BBS: +1-404-446-6336 MCI: TNIXON UUCP: ...!uunet!hayes!tnixon Internet: hayes!tnixon@uunet.uu.net
jparnas@larouch.UUCP (Jacob Parnas) (10/10/90)
In article <69427@lll-winken.LLNL.GOV>, casey@gauss.llnl.gov (Casey Leedom) writes: |> To be honest I doubt that your information is correct, but |> nevertheless, even at the known V.32bis/V.42bis expected speeds (57.6Kbps |> max (38.4Kbps ave?)) modem manufactures and others are going to have to |> beef up both their CPUs and serial chips. At some point it's going to be |> ridiculous to keep on trying to use EIA232 and we'll have to start using |> something else. Maybe even Ethernet as some have suggested ... :-) |> |> Casey Actually, several vendors have boards out that can operate at speeds up over 100000 baud. The Dickens Data Systems boards we use go up to 76800 currently. I'm told that Codex has done most of the prototyping of the 19200 baud standard and they are currently working with Rockwell to develop a standard proposal. ------------------------------------------------------------------------------ | Jacob M. Parnas | DISCLAIMER: The above message is from | | IBM Thomas J. Watson Research Ctr. | me and is not from my employer. IBM | | Arpanet: jparnas@ibm.com | might completely disagree with me. | | Bitnet: jparnas@yktvmx.bitnet \---------------------------------------| | Home: ..!uunet!bywater!acheron!larouch!jparnas | Phone: (914) 945-1635 | ------------------------------------------------------------------------------
casey@gauss.llnl.gov (Casey Leedom) (10/10/90)
/ From: jparnas@Larouch Headquarters.UUCP (Jacob Parnas) | | I heard that there is a proposal for a extension to V.32bis that will | have throughputs of 19200 baud without compression and up to 76800 with \ compression. Does anyone have any more information about this proposal? / From: casey@gauss.llnl.gov (Casey Leedom) | \ To be honest I doubt that your information is correct... / From: tnixon@hayes.uucp (Toby Nixon) | | Jacob is, in fact, correct -- CCITT Study Group XVII has initiated a | project to define the "ultimate modem" -- one that will operate full | duplex on dial-up telephone lines at rates exceeding 14,400bps. The | proposals so far call for operation at 19,200 or above, with some of the \ proposals talking about 24,000bps -- and this is WITHOUT COMPRESSION ... Jeeze, and I thought we were having a hard time now finding serial interfaces that could go fast enough. I have a feeling we're going to have to go with EIA-422. (Or is that EIA-423? What's the one with two wires for transmit and two for receive and uses differential voltage swings to determine 0/1? If I remember right it can go up to several hundred Kbps ...) But seriously, there are some serial devices which don't even go up as high as 38.4Kbps and I personally haven't seen higher rates used on EIA-232. Even V.32bis/V.42bis is going to feel choked with 38.4Kbps under some conditions. I sure CCITT is considering standardizing a modem interface at the same time ... Casey
prc@erbe.se (Robert Claeson) (10/10/90)
In a recent article casey@gauss.llnl.gov (Casey Leedom) writes: > Jeeze, and I thought we were having a hard time now finding serial >interfaces that could go fast enough. I have a feeling we're going to >have to go with EIA-422. (Or is that EIA-423? What's the one with two >wires for transmit and two for receive and uses differential voltage >swings to determine 0/1? If I remember right it can go up to several >hundred Kbps ...) That's EIA 422. EIA 423 is backwards compatible with EIA 232, but when used with an EIA 423 unit at the other end, it can go up to quite high speeds as well as to have longer cables than EIA 232. I think that the specifications says 1000 feet (~330 meters) at 19.2 or 38.4 Kbps. -- Robert Claeson |Reasonable mailers: rclaeson@erbe.se ERBE DATA AB | Dumb mailers: rclaeson%erbe.se@sunet.se | Perverse mailers: rclaeson%erbe.se@encore.com These opinions reflect my personal views and not those of my employer.
lstowell@pyrnova.pyramid.com (Lon Stowell) (10/11/90)
True, most serial chips currently sold only go up to 38.4...for
a few cents more though you can get higher speed versions up to
1.544..
RS-232 works quite well up to around 70 Kilobits as long as you
use twisted pair cabling for data and (sync only) clock leads.
I KNOW what the standard says about 20 Kbps, but have seen
thousands of RS 232 I/F's running at 56 Kbps at AT&T computer
centers....
X.21 is a nice alternative...it is an INTERNATIONAL standard (as
opposed to RS-422) and is becoming quite common on ISDN T/A's...
V.35 is quite tricky to implement--there are a LOT of verrrryyy
noisy examples on the market. Almost all of the good ones use
discrete transistors and op amps....bleeech!
It will be interesting to see how ISDN BRI affects the
superspeed 2-wire dial modems....I personally wonder if
ubiquitous BRI will happen in my lifetime......
/|
\'o.O'
=(___)=
U
THPTH! ACKHH!tempest@walleye.uucp (Kenneth K.F. Lui) (10/11/90)
In article <1990Oct9.061439.22536@actrix.co.nz> paul@actrix.co.nz (Paul Gillingwater) writes: >Hmmm.... don't look now... but I heard a rumour that Telebit have a >hot new product ready to be announced at Interop next week! Incidentally, I received a flier from Telebit about this new product. They even sent me complementary tickets for Interop and Unixpo--unfortunately, I cannot attend either because of school, oh well. Anyway, the product is called the NetBlazer. I have no idea what kind of performance it has, so don't ask me any more about it; though, if you want more info, I suggest you contact Telebit. The flier said to do that in case one can't attend both conferences (how attentive!) Ken .............................................................________________. tempest@ecst.csuchico.edu, tempest@walleye.ecst.csuchico.edu,|Kenneth K.F. Lui| tempest@sutro.sfsu.edu, tempest@wet.UUCP |________________|
floyd@hayes.ims.alaska.edu (Floyd Davidson) (10/11/90)
In article <129902@pyramid.pyramid.com> lstowell@pyrnova.pyramid.com (Lon Stowell) writes: [ text deleted ] > >RS-232 works quite well up to around 70 Kilobits as long as you >use twisted pair cabling for data and (sync only) clock leads. Did you mean to say shielded cable as opposed to twisted pair? Floyd -- Floyd L. Davidson #include /std/disclaimer floyd@hayes.fai.alaska.edu 8347 Richardson Hwy. $flame > /dev/null 2>&1 floydd@chinet.chi.il.us Salcha, AK 99714 [also related to Alascom, Inc. by a pay check, only]
csg@able (Carl S. Gutekunst) (10/12/90)
Neither twisted-pair nor shielded is a Good Thing if you are going to try to run RS-232 at high speeds (beyond 20K). Your big enemy is capacitance, both between adjacent wires (cross talk) and to ground. Nice straight wires are best. The worst thing in the world that you can do is run twisted pairs with 2 and 3 in a pair, and 15 and 17 in a pair. (I've seen it done.) Black Box sells some nice low-capacitance cables that, with modern line drivers (not the old Motorola 1488/1489 pair), you can run up to 48Kbps into 250 feet of cable and remain within spec. But they are unshielded. This is one reason it's not a good idea to run RS-232C beyond its rated speed. You really do want shielding (especially in the Midwest, where lightning is a very real problem), but it does generally increase cable capacitance. Ribbon cable is right out. :-) I think Lon mentioned that V.35 implementations tend to be marginal. So true. It's very easy to build a working, reliable RS-232 interface, yet a *lot* of them get done wrong. V.35 is much more difficult. When done right, it's very good up to T1 speeds. When done wrong, you might as well go back to RS-232. <csg>
tnixon@hayes.uucp (Toby Nixon) (10/15/90)
In article <69515@lll-winken.LLNL.GOV>, casey@gauss.llnl.gov (Casey Leedom) writes: > Jeeze, and I thought we were having a hard time now finding serial > interfaces that could go fast enough. I have a feeling we're going to > have to go with EIA-422. (Or is that EIA-423? What's the one with two > wires for transmit and two for receive and uses differential voltage > swings to determine 0/1? If I remember right it can go up to several > hundred Kbps ...) EIA-422 is the "balanced" interface (two separate wires for each signal), EIA-423 is the "unbalanced" interface (common ground, bit still uses lower voltage levels than 232 so it can go faster). The international standards the are compatible are, respectively, V.11 and V.10. Often, the "balanced"-type circuits are used for signals that change at the bit rate (data, clocks, and sometimes RTS and CTS), while "unbalanced"-type circuits are used for signals that don't change as frequently (DSR, DCD, DTR, RI). Previously, the EIA had defined only a 39-pin connector (RS-449) for use with these signals. But within the past couple of years, a new standard, EIA-530, has defined a 25-pin interface that appropriately mixes 422 and 423-type signals for a fully-functional interface. Some chip manufacturers are producing driver and receiver chips that are switchable between 232 and 530, so that manufacturers (like Hayes and Telebit) can produce modems that could support either interface. EIA-530 can support up to 1 megabit/s on cables the length typically used for modems, and rates of up to 100kbit/s over a thousand feet. The USA has proposed an EIA-530-compatible standard to both CCITT and ISO. > But seriously, there are some serial devices which don't even go up as > high as 38.4Kbps and I personally haven't seen higher rates used on > EIA-232. Even V.32bis/V.42bis is going to feel choked with 38.4Kbps > under some conditions. I sure CCITT is considering standardizing a modem > interface at the same time ... I've run EIA-232 on very short (one-meter) cables at 115,200bps without errors. Nevertheless, it is better to use the "proper" interface. People will definitely want to go to intelligent buffered serial interface cards (like Hayes ESP) when data rates get up this high. One thing I should point out is that the primary force behind pushing data rates beyond 14,400bps is NOT the demand from the asynchronous PC-type users. It is the large mainframe and networking environment, where communications is primarily synchronous and cannot benefit from the current techniques used for data compression. While those of us transferring uncompressed interactive async data streams can get up to 38,400bps today with V.32/V.42bis and up to 57,600 with V.32bis/V.42bis, these synchronous users are still stuck back at 9600 and 14,400. They're looking for something in between these rates and going to Switched Digital or Fractional T1. -- Toby ----------------------------------------------------------------------------- Toby Nixon, Principal Engineer Fax: +1-404-441-1213 AT&T: !tnixon Hayes Microcomputer Products Inc. Voice: +1-404-449-8791 CIS: 70271,404 Norcross, Georgia, USA BBS: +1-404-446-6336 MCI: TNIXON UUCP: ...!uunet!hayes!tnixon Internet: hayes!tnixon@uunet.uu.net