korn@altger.UUCP (Hans Korneder) (03/15/89)
In article <4377@drivax.DRI> braun@drivax.DRI (Karl T. Braun (kral)) writes: >I'm trying to setup a connection with one of our sites in Germany. Apparently >they have very stingent rules concerning what kinds of equipment can be used >over their telco lines. I know that a lot of 2400 baud modems have been >'approved' for use there; does anyone know of any faster modems that have >likewise been approved? (TB+ is approved, but only 2400 and lower). The German Bundespost just started a *large* field-test (some 50 sites involved) with the Telebit Trailblazer (modified a bit by Kabelmetall Elektrik to allow 1200/75 Baud, to use Bundespost-plugs instead J11, etc.) According to Bundespost-insiders, this modem is about to being approved by the end of this year. (hopefully). But anyhow: I guess, you won't be very happy with a TB+ across the ocean: The TB-modems do some sort of token passing between the modems when they are idling. If you dial and get a sattelite-line, there are *some* delays on the line, which make it almost impossible for that mechanism to work. (At least those were my experiences). TB's perform excellent on lines thruout Europe; They hardly set up a link across the ocean.. -- Hans Korneder SNAILMAIL: Altos Computer Systems UUCP: korn@altger.uucp Wuermstrasse 55 BANG: ...!uunet!mcvax!unido!altger!korn D-8032 Graefelfing (Germany)
w-colinp@microsoft.UUCP (Colin Plumb) (03/19/89)
korn@altger.UUCP (Hans Korneder) wrote: > But anyhow: I guess, you won't be very happy with a TB+ across the ocean: > The TB-modems do some sort of token passing between the modems when they are > idling. If you dial and get a satellite-line, there are *some* delays on > the line, which make it almost impossible for that mechanism to work. (At > least those were my experiences). This seems very odd; I thought the Telebit guys were smarter than this and could cope with long-latency lines. They're certainly aware (uucp spoofing an all) of how badly simplistic protocols die in the face of longer latency. -- -Colin (uunet!microsoft!w-colinp) "Don't listen to me. I never do." - The Doctor
piet@cwi.nl (Piet Beertema) (03/21/89)
TB's perform excellent on lines thruout Europe; They hardly set up a link across the ocean.. Not entirely true: that's the case if both sides have the 4.0 software revision level; if either side (or both) have the 3.0 level it works just fine. Of course it suffers from the normal 3.0 drawback: very slow for interactive use; but it's fast in batch mode (like uucp). Supposedly Telebit has come up with a newer 4.x version that should have solved the problems of transatlantic links, while maintaining good interactive speed, but sofar I haven't seen any sign of that new release. -- Opinions expressed above reflect those of my employer, except when they don't. Piet Beertema, CWI, Amsterdam (piet@cwi.nl)
patg@impch.UUCP (Patrick Guelat) (03/21/89)
In article <1445@altger.UUCP> korn@altger.UUCP (Hans Korneder) writes:
#
#But anyhow: I guess, you won't be very happy with a TB+ across the ocean:
#The TB-modems do some sort of token passing between the modems when they are idling.
#If you dial and get a sattelite-line, there are *some* delays on the line, which make it
#almost impossible for that mechanism to work. (At least those were my experiences).
#
#TB's perform excellent on lines thruout Europe; They hardly set up a link across the ocean..
I think there is an undocumented register in v4.0 of the firmware, that allows
you to disable the little packets (the ones for interactive use). As far as I
can remeber it's register 120 that allows you to set different packet modes.
Possibly you have to set 120=2 to allow long packets only, but I'm not
sure.. Perhaps telebit can answer this and tell us if there are other
undocumented registers.
BTW, we use a Telebit TB+ that we've got from the U.S. here in Switzerland,
Europe. I heard that the new firware (v4.0) supports V21 and V23. If this is
true, it would be nice to know how to use this features ! (eg. V21 fallback
for our poor 300 bps users.. ;-)
-Pat
--
\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//
// Patrick Guelat, boxdiger@impch ......!backbone!impch!{boxdiger,patg} \\
\\ Wasting time is an important part of living. //
//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\korn@altger.UUCP (Hans Korneder) (03/21/89)
Some days ago I posted my problem with Telebit Trailblazer modems
(version 4.00 firmware) with satelite links across the ocean.
Meanwhile I've got a solution. To summarize:
In article <12374@microsoft.UUCP> w-colinp@microsoft.uucp (Colin Plumb) writes:
)korn@altger.UUCP (Hans Korneder) wrote:
)> But anyhow: I guess, you won't be very happy with a TB+ across the ocean:
)> The TB-modems do some sort of token passing between the modems when they are
)> idling. If you dial and get a satellite-line, there are *some* delays on
)> the line, which make it almost impossible for that mechanism to work. (At
)> least those were my experiences).
)
)This seems very odd; I thought the Telebit guys were smarter than this and
)could cope with long-latency lines. They're certainly aware (uucp spoofing
)an all) of how badly simplistic protocols die in the face of longer
)latency.
They are smarter...
)From: piet@cwi.nl (Piet Beertema):
) TB's perform excellent on lines thruout Europe; They hardly
) set up a link across the ocean..
)Not entirely true: that's the case if both sides have
)the 4.0 software revision level; if either side (or
)both) have the 3.0 level it works just fine. Of course
)it suffers from the normal 3.0 drawback: very slow for
)interactive use; but it's fast in batch mode (like uucp).
)Supposedly Telebit has come up with a newer 4.x version
)that should have solved the problems of transatlantic
)links, while maintaining good interactive speed, but
)sofar I haven't seen any sign of that new release.
Not entirely true, too...
)From: piet@cwi.nl (Piet Beertema):
) Watching the lights, it *looks* like there are 7 exchanges then
) a significant (1-3 seconds) pause before communications continues.
) Has anyone seen similar performance
)Yes.
) and fixed the problem ?
)yes: go back to 3.0 software level.
)
) Both telebits are using version 4.00 ROMs
)The problem is in 4.0; and you can *hear* it going wrong:
)first give "atm2" to constantly enable the speaker, then
)set up the connection by hand. And then listen to the
)endless retrains/renegotiates of the modems trying to get
)"in sync" again; those are the pauses you observe.
)
Don't go back to 3.0 software-level...
Well, all those replies were correct, I noticed exactly the same
strange retrains/renegotiations.
But then I set the register: S120=12
(Don't complain, please... I don't have any description of register 120..
I didn't even know, there was a register 120 before...,
AT&W doesn't save register 120, so include it into your dialer-script,
I've got that information from Rick Adams, ...)
And guess, what happened: The modem transferred text files across the
ocean at a rate of > 1700 chars/sec, without retrains/renegotiations etc..
Hope, you can share my good experience..
Hans
--
Hans Korneder SNAILMAIL: Altos Computer Systems
UUCP: korn@altger.uucp Wuermstrasse 55
BANG: ...!uunet!mcvax!unido!altger!korn D-8032 Graefelfing (Germany)braun@drivax.UUCP (Kral) (03/22/89)
In article <844@sering.cwi.nl| piet@cwi.nl (Piet Beertema) writes: | Not entirely true: that's the case if both sides have | the 4.0 software revision level; if either side (or | both) have the 3.0 level it works just fine. Of course | it suffers from the normal 3.0 drawback: very slow for | interactive use; but it's fast in batch mode (like uucp). | Supposedly Telebit has come up with a newer 4.x version | that should have solved the problems of transatlantic | links, while maintaining good interactive speed, but | sofar I haven't seen any sign of that new release. I have two TB+s that we bought during the December close out. How does this affect us (we are trying to set up links with the UK and Germany)? How do I know which software version I have? What, exactly, are the "problems of transatlantic links"? Have I used up my monthly quota of dumb questions yet? -- kral 408/647-6112 ...{ism780|amdahl}!drivax!braun "To surrender is to remain in the hands of barbarians for the rest of my life; To fight is to leave my bones exposed in the desert waste" - ancient chinese poem
jbayer@ispi.UUCP (Jonathan Bayer) (03/27/89)
In article <729@impch.UUCP> patg@impch.UUCP (Patrick Guelat) writes: > >I think there is an undocumented register in v4.0 of the firmware, that allows >you to disable the little packets (the ones for interactive use). As far as I >can remeber it's register 120 that allows you to set different packet modes. >Possibly you have to set 120=2 to allow long packets only, but I'm not >sure.. Perhaps telebit can answer this and tell us if there are other >undocumented registers. I was recently talking with Bob Boynton at Telebit, and the subject of my problems connecting with UUNET over the 800 lines came up. He described register s120, and suggested I try setting it to 2. I did, and all my problems went away. I have included a short description of the register below. It is a bit-mapped register, and using other values won't do anything. Bob said that using a value of 2 might come up with a net loss of about 15% throughput, however I have not noticed any reduction. s120= 0 when modems connect, and exchange info, will attempt to connect at the shortest possible packet 12 forces modem to abondon micropacket (faster on long distance lines) 2 long packets A suggestion he suggested was to turning the speaker on at all times (atm2). If you hear a lot of retrains (period of silence followed by re-syncing sound heard upon initial connect) then try setting s120=2. JB -- Jonathan Bayer Beware: The light at the end of the Intelligent Software Products, Inc. tunnel may be an oncoming dragon 19 Virginia Ave. ...uunet!ispi!jbayer Rockville Centre, NY 11570 (516) 766-2867 jbayer@ispi.UUCP