PC Card Sportster X2--Battery Power vs. AC Power

PC Card Sportster X2--Battery Power vs. AC Power

Post by Adam M. Espeset » Sun, 09 Nov 1997 04:00:00



I have a strange and annoying problem.  I recently purchased a USR Sportster
SP1336 PC card modem for my IBM Thinkpad 385ED.  I flashed the modem to X2
right after I got it.  However, I have noticed that now modem performance
depends on how the laptop is powered (battery or AC).

If I connect to my ISP when the laptop is plugged in, Win95 reports a 48kbps
connection (every time) and throughput is AWFUL!  I get 1k/sec downloads and
sometimes even slower.  If I unplug the laptop so it runs off of the battery
(while it is still connected), throughput goes up to what I would expect
with an X2 modem.  If I connect to my ISP when the laptop is powered by the
battery, throughput is great.  If I then plug the machine in to AC power,
downloads will slow to a crawl.

This is extraordinarily annoying!  Now I need to make sure my battery has a
good charge before I connect to the internet and surf the web.  I sure wish
it was the other way around--you usually have an AC outlet handy if you
happen to be using a modem.

I have tried everything!  At first I thought my power management was messed
up, but those settings don't seem to make a difference.  I've tried dimming
the display, turning off the display, using different AC outlets and phone
jacks, yada yada yada.  I sent USR a few different emails about this
problem, but they just sent a generic "problems with X2" form letter.

Should I be bothering USR (3com) or IBM?  As far as I can tell, I'm using
the latest drivers for the modem.  If ANYONE has any suggestions I would
greatly appreciate it!

Thank you very much!

Adam Espeseth

 
 
 

PC Card Sportster X2--Battery Power vs. AC Power

Post by Ogden G. War » Sun, 09 Nov 1997 04:00:00


The problem appears to be with noise from your power supply/battery
charger.  This is a common problem with portable ham radio equipment
and also with some portable computer equipment.  You may have to try
another power supply. Some of the supplies were designed with barely
enough capacity to handle the computer and its internally contained
components when the battery is low. So the additional drain of a
PCMCIA card modem overloads the power supply.  The more load you put
on these under-designed power supplies, the noisier their output gets.

If you know someone with the same computer, try their power supply.
If theirs works OK with your modem, then replace your power supply.
If the results are the same, see if the computer manufacturer has a
power supply with greater capacity available. If this is also your
primary computer for home use, you may want to look into getting a
good docking station for it.  Some have better power supplies built
in.

Bottom line could well be that your only solution is to only use the
modem when your computer battery has a fresh, full charge.

I sure wouldn't blame the modem company for the problem, they didn't
design and build the power supply.

O.G. Warth
-----


>I have a strange and annoying problem.  I recently purchased a USR Sportster
>SP1336 PC card modem for my IBM Thinkpad 385ED.  I flashed the modem to X2
>right after I got it.  However, I have noticed that now modem performance
>depends on how the laptop is powered (battery or AC).

>If I connect to my ISP when the laptop is plugged in, Win95 reports a 48kbps
>connection (every time) and throughput is AWFUL!  I get 1k/sec downloads and
>sometimes even slower.  If I unplug the laptop so it runs off of the battery
>(while it is still connected), throughput goes up to what I would expect
>with an X2 modem.  If I connect to my ISP when the laptop is powered by the
>battery, throughput is great.  If I then plug the machine in to AC power,
>downloads will slow to a crawl.

>This is extraordinarily annoying!  Now I need to make sure my battery has a
>good charge before I connect to the internet and surf the web.  I sure wish
>it was the other way around--you usually have an AC outlet handy if you
>happen to be using a modem.

>I have tried everything!  At first I thought my power management was messed
>up, but those settings don't seem to make a difference.  I've tried dimming
>the display, turning off the display, using different AC outlets and phone
>jacks, yada yada yada.  I sent USR a few different emails about this
>problem, but they just sent a generic "problems with X2" form letter.

>Should I be bothering USR (3com) or IBM?  As far as I can tell, I'm using
>the latest drivers for the modem.  If ANYONE has any suggestions I would
>greatly appreciate it!

>Thank you very much!

>Adam Espeseth



 
 
 

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