Baslinux mailing list

[Samual Acorn <sam.acorn AT gmail.com>]

On 29/12/05, sindi keesan <keesan AT sdf.lonestar.org> wrote:
> On Thu, 29 Dec 2005, Samual Acorn wrote:
>
> > On 28/12/05, sindi keesan <keesan AT sdf.lonestar.org> wrote:
> >> I have two modems and was using the same init string with both (S15=128
> >> added).  Both are USR but only one is apparently Sportster.
> >>
> >> The S15=128 disabled MNP in the Sporster, but was enabling it in the 
> >> other
> >> USR.  I changed that init string to AT&F1 (specific to USR, hardware flow
> >> control)  Now they are both V42bis (eznet log) and the non-Sportster has
> >> doubled its upload speed.  They both connect at 50666/31200.
> >
> > MNP should have been disabled by default.... useless in todays world...
>
> I removed S32=34 in the Sportster string and it stays at V42bis.
> In the other USR is appears to turn ON MNP instead of V42bis.
> I will delete it everywhere.

i cant remember what the command is but you can save configuration
data to the modem (the command is the same for all modems... i -think-
its W0 but double check on that) that way you wont need to juggle init
strings around but your modem will be set as soon as you turn it on
(ATZ or AT&F1 will be all that you need in the dialer... ATZ and AT&F1
do the same thing as far as configs go ATZ just clears memory... makes
for a cleaner reset)

>
> S15=128 seems to keep the Sportster from attempting to use X2, so it
> negotiates and connects faster.  The non-Sportster boings for a lot
> longer.

the 'boing boing' is the modem testing the analog frequency response
of the phone line... the modem on the other end will answer with a
simple beep when testing is successfull (if testing is not successful
you will not get 56k)

btw, other modems make different noises for the frequency response
test.... rockwell/conexant make a "brrrrrrrraaaAAAP" (sounds like a
synthesiser trying to make a fabric ripping noise... or the result of
a bean burrido) and agere intel and possibly others make a "diddledy
diddledy" (almost like an electronic giggle)

>
>
>
> >> S32=34 stops the Sportster from trying to connect with SX2 but has no
> >> effect on the other USR.
> It does not stop the Sportster, I was wrong.

x2 and flex should be disabled entirely.... they are obsolete unstable
and unused by ISPs....

>
> >>
> >> A comparison of ati output reveals the internal non-Sportster is a bit
> >> newer.  It uploaded a bit faster, but the Sportster had a higher actual
> >> peak speed for download.
> >>
> >> ati6 - gave the upload and download speeds, 50666/31200 for both, but the
> >> external actually connected at 53333 and this was the peak speed.
> >> How can it run faster than it connected?
> >
> > the initial connect speed is an idea... not an absolute... the modem
> > will change speeds (up and down) throughout the connection as line
> > conditions change...
>
> It connected at 53333 but ran at 50666?

it connected at 53333 and the line conditions changed and it realised
that that speed wasnt stable and did a re-train and slowed itself down
to 50666.... its also possible for 56k modems to increase the speed if
the opportunity arrives so even if it slows itself down it may speed
itself back up.... or it may even speed up faster than the inital
connect speed....  add M2 to your init string to make the modems
speaker stay on all the time and you'll hear whats going on..... itll
get a wee-bit irritating after a while tho....

>
> >> ati7:
> >>
> >> Non-sportster:  FLASH date 4/22/98, 4.7.35
> >> V32bis, V80, V34+, X2, V90
> >> Why is V42bis not listed?
> >
> > probably doesnt support it(or a lazy programmer didnt add it to the
> > ATI string reply).... and is using v34 rather than v42 if you disabled
> > MNP... check for upgrades...
>
> It uploads faster without MNP and when I connect eznet log says V42bis.

i dont use eznet (i use bash chat and pppd) so i dunno what to tell
you but if the modem supports and is using v42 but it doesnt tell you
it supports it or tries to use MNP rather than v42 that just sounds
like some crappy programming (welcome to the world of us robotics
products)

>
> >> Did post 1998 modems eliminate MNP?  Most of ours are 1997 because we got
> >
> > they didnt elimitate it... but use it as a fallback if the modem on
> > the other end of the line doesnt support v34 v44 or v42... actually
> > all modems that support at least v42 should... but  yours seem not
> > to.... are you sure they are using v42? if they only support v34 then
> > they will try to use MNP....
>
> eznet says V42bis, at connect time
>
> >
> >> them free as 33.6K, and upgraded.  They need to be X2 to start with 
> >> before
> >> you can upgrade to V90, not just 33.6K.  1997 was the year of three
> >> standards, after which only V90 or V92 (or ?).  What was the third, 56
> >> Flex?
> >
> > x2 and flex were the starters... they were proprietary... not
> > standards... v90 was the standardized version (using the best parts of
> > both) and v92 is a recent addition adding faster uploads(pcm upstream)
> > and better compression(v44)....
>
> Is the upload same speed as download?  How fast would v90/v44 upload a
> .jpg?


v90 has a max downstream of 56000 (53333 in the us due to power output
restrictions... tho this was recently changed many ISPs just left
things alone) and a max upstream of 32000 (v90 56k modems were
designed with only web surfing in mind... so they upload slower than a
33.6k modem)  v90 does not support v44 compression... only v42... v42
does not do a very good job of compressing jpegs so the data rate of
the modem itself is all you are going to get (think of it as if
compression wasnt even enabled)

v92 supports max 56000(53333) down and max 48000 up (they realised
that ppl actually -wanted- to upload) and the multimedia friendly v44
compression (yes... it can compress jpeg data... think of v42 as .zip
and v44 as bzip2 or rar)


>
> >
> > what are the model numbers of your modems? (sticker on the modem)
>
> One is internal, the other Sportster 0459.  Case says 1995, but they were
> originally used with 14.4K modems.

i find nothing on a model 0459 (does not exsist on the USR site)...
what are the FCC ID numbers on the circuit boards? (since -- as i
understand it -- you are using a different case for the external?)

>
> When dialed to the bbs at 14.4 I don't get the 20 sec freezeups, at 56K I
> do.

those 20sec freezeups are speedchange retrains.... if you use M2 you
will hear a full retrain during those pauses...

14.4k is technically the most stable speed a POTS line can handle....
anything faster is pushing the laws of physics...

>
> FTP downloads get progressively faster, to about 3K, and uploads get
> slower, to about 3K.

TCP/IP slow start (for downloads) and modem buffering (for uploads)...
3K is what you are stuck at it seems...

>  I think the long wait at the end of kermit file
> transfer (with Window Slots decreasing from 30 to 1) is when the modem

ive never made any use of the kermit file transfer protocol... zmodem
is the only thing ive used thats that old... and that was over a
nullmodem cable.... i have no info/idea on how kermit would/should act
over dialup...

> buffer finishes unloading, and the 25K decreasing to 2K is because it is
> getting data faster than it can send it.  Is there any advantage in
> setting port (connect) speed with pppsetup to 115200 instead of 57600?

should use 115200 with all modems.... that is unless they dont/wont
support it (seems only very old 14.4k modems dont) need some room for
compression to do its thing.... ever see a 14.4k modem do 6K/s? (AT&T
paradyne.. commercial/business grade)...

>
> >>
> >> Sindi
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--
--sam
http://mephitus.renamon.org/
"When you've done something right, no one will be sure you've done
anything at all." -- Futurama
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