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baslinux - Re: [BL] slow upload speed, was Re: multiple systems (among other things) -- was Re: interesting info for those with trident cards (possibly applies to others)

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  • From: sindi keesan <keesan AT sdf.lonestar.org>
  • To: baslinux AT lists.ibiblio.org
  • Subject: Re: [BL] slow upload speed, was Re: multiple systems (among other things) -- was Re: interesting info for those with trident cards (possibly applies to others)
  • Date: Sat, 31 Dec 2005 23:52:28 +0000 (UTC)


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)

You mean the phone jack? I can plug it in and out a few times.

yes.. the phone jack in the modem... had (still have) a gateway 2000
telepath 14.4k internal that had some serious issues till i took a
flat-blade screwdriver and scratched it across the metal pins to get
the corrosion off... worked perfect till i 'took it out of service'...
replacing it with a rather flaky 33.6k (never did find out what was
wrong with that one... wasnt connection problems but power-on
problems... long story....)


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...

I have ISA SCSI card in that computer and this is an ISA modem. (Are
there any pci hardware modems?).

there are a few... but they use a different means (of course) to
communicate rather than the standard UART... they need software to
make them act like a regular com port in dos which isnt always the
best at compatibility (but it does work) but performace of a hardware
pci vs. isa is neglegable when used with OSs like linux or windows....
when it comes to PCI modems tho buyer beware...

I try to put the modems as far as
possible from the power supplies.

PSUs are sheilded in their own case... putting a modem close to one
wont hurt.... what i ment by noisy was the power supplied by the
PSU... an overloaded or tired (near the end of usefull life) PSU can
make noise (low amounts of AC or even RF) on the normally pure DC
power connectors... causing all kinds of random weirdness from modems
not wanting to work properly to "hum bars" on the monitor to
spontanious reboots

We had one power supply that interfered with radio reception upstairs ten feet away, and made it impossible to use a modem in the computer.


putting the modem near a scsi card or video card thats particularly
noisy (RF noise... usually from poor design) can cause interference
with the modem....

So do I put the sound card in between scsi and modem?


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

I will look online for this. Just found a Supraexpress manual 28.8
AT+MS=? lists supported options
%CI MNP 5 enabled
%C2 V.42bis enabled
%C3 V.42bis and MNP 5 enabled (Default).

They recommend turning OFF compression when transferred already-compressed
files such as ZIP, because it may actually go faster. I will try it.

make sure to only turn off compression and not error correction... (i
made that mistake once... things went from slow to useless very
quickly)


USR Sportster 14.4K manual (but my modem is 56K)
&K0 data compression disabled
&K1 auto enable/disable (default) - The modem enables compression if the serial port rate is fixed, and disables compression if the serial port rate follows the connection rate. (Compression offers no throughput advantage when serial port and connection rates are equal, and may even degrade throughput).

&B1 - serial port rate fixed
&B0 - serial port rate follows connection rate
AT&F1 chooses defaults for USR and &B0 is the default, which means
compression is already disabled, but my enabling MNP halved the speed.
This must refer to V42.bis only.

&K2 Data compression enabled
&K3 Selective data compression. disables MNP and uses V.42 bis only if the file is not already compressed.

I tried with the default (which is disabled compression) and with &K3 (compress only if not already compressed) and ftp downloaded an .ogg file.
Default setting: 50 sec, 4061 cps
&K3 (checks to see whether to disable it): 60 sec, 3841 cps
My download speeds are rather variable anyway, from sdf, so this is within the margin of error.

I could do this test with a file which is not already compressed but I don't generally download large text files, just zip, jpg.

I could try &B1 fixed serial port rate and compression enabled.

The default is disabled compression.

%E Do not request a retrain (default)
%E1 Monitor line quality and automatically request a retrain if line
conditions are bad.

&K commands - flow control

flow control should be set to hardware (in both the modem and your software)
It is the default.


Gateway Telepath 28.8 - supports full Hayes AT command set
Data compression: V.42bis and MNP5 bps to 115,200 bps throughout. Modem
also operates without data compression (maybe this would work better for
jpegs?)
ATI 0-7
No %-type commands like the Supra.
&K0 - Data compression disabled
&K1 Auto enable/disable (default)
&K2 - Data compression enabled
&K3 - MNP5 compression disabled

Similar to the USR, less useful manual.

Obviously different modems use different commands. I have a few USR
manuals around some place and will experiment.

hayes standard is supposed to be universal (but its very simple...
similar to the commands used with 9600 bps and less modems)

It was not universal for all the 14.4K or older.

hayes extended is also supposed to be universal but quite a few
manufacturers dont use it... newer USRs in particular.... zoom uses
it....

But people around here have a choice and many still use dialup.

well... keep an eye out then.... most anything dated 1998 and pretty
much -everything- dated 1999+ will either be v92 or v92 flashable...

I will check ours for late 1998's. I already flashed the 1997s X2s to V90 with early 1998 files.

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

Mine are 1997 and I already flashed them all.

no newer flash updates available?
That was what I found for them, v90, dated early 1998.

A friend who thought his phone lines only supported 28K discovered he
could get 40K with a USB modem (after the onboard one died).

i can get ~45k/s down its the upspeed i have problems with.... checked
not to long ago to be at ~21k (always gets worse when the temperature
cant make up its mind [frigid nights and hot days].. its just
something ive come to be used to...)


I could try doing email online at a slower speed.
If I told it not to retrain what might happen?

if things got bad the connection would instantly drop or become very
unstable... (ive tried that one too)

Skip it. I am satisfied with 3K/sec uploads, beats 1.5K.

Mine are not new. I have a Hayes external that used to be 56K.

used to be?

It is labelled 56K but downloads like a 28K. I have two, the other worked as 56K until lightning struck. A USR 56K after the same lightning storm changed to 14.4K max. Some day we may find the bad part, if people don't give us more old modems.

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)...
lines.... ever called anyone by using the hook switch to dial their
number? ;) )

No, how?

pulse dialing... switch your phone to pulse and put the headset to
your ear and dial your own phone number (so as not to bother anyone
else)... if you have good rythm make a mental note of how the 'pop -
pop - pop' noises are spaced... (the technical term for this is 'make
and break ratio')... then... emulating the tempo of pulse dialing to
the best of your abilities its possible to quickly tap the hook switch
to dial phone numbers.... for instance tapping 5 times at the pulse
tempo then waiting for the amount of time normally taken before the
next number in the string is dialed then tapping 5 times again would
dial the number "55"... tap once for 1, twice for 2, and so on... 0 is
dialed using 10 taps... its very tedious but it does work... (expect
to get a few "wrong numbers" and "this number cannot be completed as
dialed" automated messages)

I guess we should not have thrown out the old dial phone that would no longer dial properly because the connections wore out, but used it this way.

How do you dial a bbs without a terminal program, echo atdt1234567 > /dev/ttyS1, etc.?




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