Baslinux mailing list

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

On 30/12/05, sindi keesan <keesan AT sdf.lonestar.org> wrote:
> > 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)
>
> AT&F1 works fine for me with USR, no need to change it.  Most of my modems
> are USR.  I just need to remember to use ATZ on the others.

well.. if its working...

>
> >>
> >> 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)
>
> So why is the internal (slight newer) modem with the slightly older flash
> taking longer to connect?

multiple causes for this one;

the modem is just trying to be more thourough in its check

bad programming causing problems during the check

corrosion on the pins in the jack causing noise or signal loss (make
sure they are shiny)

since its internal may be getting interference from a nearby card
especially if it uses a transformer for phone line isolation (scsi is
a bit noisy) or the PSU might be noisy (checked the modem in multiple
systems?)  note: this one is rare but not unheard of...

if it uses relays to 'pick up the phone' rather than solid state
components the contacts may be corroded... (this one is something best
left alone)..  rare as well but still not unheard of...


>
> > 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)
> Interesting.

just some usless trivia gathered while tinkering with different brands ;)

>
> >>>> 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....
> I thought S15=128 was supposed to disable X2 but maybe only for the
> Sportster, which is why it connects with less boings.
>
> Ijust had a 20 sec timeout again.

check your manual for an option for 'quick retrains' and make sure its
turned on (if available)


>
> > 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....
>
> It always connects at 53333 and then ATI6 always says 50666.
> My other modems run about 46-49K.  These are the best two.
> (There is a newer one that is 56K but connects at 28.8K).
>
> > 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)
>
> It only uses MNP if I tell it S32=34
>
> >>
> >> 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)
>
> This must be why we are finding used 56K v90 for $1 (one of the three
> actually worked at about 56K).  With people now switching to DSL, maybe a
> non-winmodem V92 will show upused.

er... i woudnt count on that... the ppl buying hardware v92s are those
who are -stuck- with dialup...

also many newish hardware v90s are flashable to v92 (USR has linux
flashers... might want to look into this one)

>
> Shrinking the jpegs helps more than compression.

of course.. i didnt mean for you to -rely- on compression but just
saying that it can help...

>
> >>> 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?)
>
> The 0459 came in that case, I meant that the case was dated 1995 because
> they were first made then and used with 14.4K modems.
> I may have read this wrong, upside down with a flashlight.  We have
> another similar one that came as V90 not X2.

check for V92 updates on the one that came as V90... if that was its
original configuration...

>
>
> >
> > 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...
>
> If I dialed in at a slower speed would it freeze up less often?  For
> writing and reading email the speed is less important than a lack of
> freezeups.  I get freezeups even with a 33.6K modem, should I try 28.8K?

28.8 would freeze too (26.4 is a more common speed than 28.8... phone
lines simply werent ment for data... and i have the unfortunate
situation of only being able to reach 24.0 with analog (28.8 & 33.6)
connections/modems...

>
> >> 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...
>
> 3.3K.  With a 33.6K modem.  3.1K with 56K - but variable.  Would a 33.6K
> speed actually upload faster overall, because of fewer freezeups?

yep... if you do more uploading and general traffic than just surfing
the web a 33.6K might be better than a 56K...

>
> Should I set connect speed to not 115200 but 57600 for 56K 1998 modems?

if the modem supports 115200 use it... if not use the next highest
speed... even the modem makers say this...

>
> >
> >>  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)...
>
> I will check our 14.4K ATT (if I did not already recycle it).
> Does anyone but Rockwell and USR make 56K internal hardware modems?

i didnt even know rockwell was still making hardware internals... only
hardwares i can find are externals... (zoom and usr) PCI hardware
modems arent... compatible enough for my tastes...
ISA cards and ISA mobos are specialty items in todays market (if we
are talking new hardware anyway)

>
> We had one external 56K Sportster that produced garbage at 152000, worked

bad programming...cant remember what the bug was in (i think there was
an Sregister that had to be changed) but look for an update... (altho
you did say 'had' so i guess you dont have it anymore)


> at 57600. Maybe broken somehow.  They keep working despite problems (such
> as taking the phone offhook as soon as you turnthem on,

if they dont take the phone off-hook while turned off but still
plugged in check for Sregister settings that may have been changed to
cause this.....

> only running at
> slow speeds,

corrosion, noise, bad programming... incorrect Sregister settings...


needing to be told to go offhook before you dial....)

that one is definitly software related....

> Lightning damage?

possible on the one that stays off-hook and the slow one but modems
usually have lightning protection... if the strike actually makes it
through its usually the end (cant pick up the phone at all or
completely dead) ... i have a USR 5686D flashed to V92 that was struck
by lightning... ATH1 (go off hook) ATX3DT (blind dial) both cause a
click noise and "ERROR" .... it never dials out or can even pick up
the phone.... AT&T1 (internal analog loopback test) works tho.... so i
have a 90$ paperweight that responds to AT commands and nothing
else..... ugh... (i can even do flash upgrades on it... not that it
does me any good)

a friend once asked (quite some time ago) if it would be possible to
use a modem as an ad-hoc soundcard (play music through its speaker)...
i told him i would need some sort of low-level access to the
DSP/datapump to do that.... guess i have a candidate for
experementation... (USR modems -are- rather extensivly documented)

>
> Thanks for all the helpful info.  Where did you learn so much about
> modems?

"hacker" mentality stuck on dialup since 1997?.... (i read in the
jargon file that those with a hacker mentality tend to absorb and
retain massive amounts of "useless" data)

mainly i just like taking things apart to see how they work and if
they can be improved in any way or made to do things 'they arent
supposed to do'.... and watching clocks slowly count backwards all the
time has lead me to learn everything i can about modems and phone
lines.... and ways to try to speed those clocks up.... (and as a
side-effect... learning a few other things related to modems/phone
lines.... ever called anyone by using the hook switch to dial their
number? ;) )


>
> >>>> Sindi
> _______________________________________________
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> BasLinux AT lists.ibiblio.org
> http://lists.ibiblio.org/mailman/listinfo/baslinux
>


--
--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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