56K Modem will not get higher than 24K

[just-me]

Several weeks ago I posted some messages on here trying to determine
why my dialup connection suddenly dropped from around 44K to always
connecting at 24K. I tried most of the tests you all recommended,
spent days trying all sorts of diagnostics, calling my ISP, the phone
company, etc. I finally ordered another external modem (because I got
tired of fighting with the internal ones that dont have drivers for
Win98).

I just got the new modem. Installed it, and I am once again getting
44 to 45K.

Why would the old modem suddenly just quit connecting at any speed
higher than 24K? It always used to connect at 40K or higher, and I
used it for years. It just suddenly started to connect at 24K and I
have lived with that for almost a month.

There could have been a lightning surge, but having had a few other
modems die from lightning, they normally just die completely. I just
can not understand why this old one just dropped to 24K and will not
connect higher. The old modem is a US Robotics 56K Voice Pro PNP.
(which was a top of the line modem).

This makes no sense to me....

Thanks

 

[Paul]

Several weeks ago I posted some messages on here trying to determine
why my dialup connection suddenly dropped from around 44K to always
connecting at 24K. I tried most of the tests you all recommended,
spent days trying all sorts of diagnostics, calling my ISP, the phone
company, etc. I finally ordered another external modem (because I got
tired of fighting with the internal ones that dont have drivers for
Win98).

I just got the new modem. Installed it, and I am once again getting
44 to 45K.

Why would the old modem suddenly just quit connecting at any speed
higher than 24K? It always used to connect at 40K or higher, and I
used it for years. It just suddenly started to connect at 24K and I
have lived with that for almost a month.

There could have been a lightning surge, but having had a few other
modems die from lightning, they normally just die completely. I just
can not understand why this old one just dropped to 24K and will not
connect higher. The old modem is a US Robotics 56K Voice Pro PNP.
(which was a top of the line modem).

This makes no sense to me....

Thanks

If the damage to the analog front end, affected the frequency
response, then that could account for a lower connect rate.
(It is unfortunate, that all the pictures in this article,
did not get archived.) It isn't something I would have
thought of, or considered, because the analog front
end should be pretty simple (maybe a transformer with
capacitive coupling - not really sure - some front ends
are "silicon" and don't use the older methods). The front
end is there, to protect the user's computing equipment,
from the voltages and transients found on telephony
equipment. For example, ringing voltage from the
ringing generator, are enough to give you a shock, and
the front end on your modem is there, to isolate those
voltages, so they don't get to any 5V or 3.3V logic chips.

http://web.archive.org/web/20021213093330/http://gate.cruzio.com/~jeffl/aty11/aty11.htm

The rest of the graphs can be found here.

http://members.cruzio.com/~jeffl/aty11/?N=D

The above graphs are constructed from the data collected
with the ATY11 command. If you compared the ATY11 data
from the old modem to the new modem, it would allow
comparisons like Jeff was making.

Congratulations on getting your speed back

Paul

 

[Flasherly]

Several weeks ago I posted some messages on here trying to determine
why my dialup connection suddenly dropped from around 44K to always
connecting at 24K. I tried most of the tests you all recommended,
spent days trying all sorts of diagnostics, calling my ISP, the phone
company, etc. I finally ordered another external modem (because I got
tired of fighting with the internal ones that dont have drivers for
Win98).

I just got the new modem. Installed it, and I am once again getting
44 to 45K.

Why would the old modem suddenly just quit connecting at any speed
higher than 24K? It always used to connect at 40K or higher, and I
used it for years. It just suddenly started to connect at 24K and I
have lived with that for almost a month.

There could have been a lightning surge, but having had a few other
modems die from lightning, they normally just die completely. I just
can not understand why this old one just dropped to 24K and will not
connect higher. The old modem is a US Robotics 56K Voice Pro PNP.
(which was a top of the line modem).

This makes no sense to me....

I'm not the fan of USR I once was, although were I there's probably
USR modems models (Sportster/Courier?) I would prefer. Zoom and Supra
were the last couple I got (under $20ea), still brand new in boxes
that'll probably end in the garbage can. VOIP runs me about $20
mnthly these days.

There are associated commands for forced speed connects - it simply
won't connect at less and drops carrier rather than retrain (or
retrain while always above another command variable, for lowest
permissible retrain speed). Between all that, they can be finely
tuned in.