Sorry to disappoint you Jonathan
The rate reported by wvdialconf is not the transmission rate! It is
(supposedly, never checked, irrelevant) the rate at which the software
communicates with the serial connection to the modem chip located in the PC.
You will see the true rate when you launch a wvdial command. wvdial
will report the word "CONNECTED" and the rate, and it will never reach
the theoretical 56kbauds limit.
Just to tease you, though, I am currently working flawless with a serial
connection at 460,800 bauds. But not the way you think of.
I use a Xilinx Spartan 3AN FPGA development board as a data acquisition
system. It has an RS232 port which can go even at least twice faster
than 460,800. I have connected it to a 10-15$ RS232-to-USB adapter with
a shielded cable 20cm long only or it won't work, and the USB side of
the adaptor is connected to my laptop with a 40cm shielded USB cable or
it will not work.
Actually while pushing the above to its limits to match the data
acquisition system specifications, I "discovered" that the 115200 bauds
limit which everybody knows about is just what was set in the initial
version of National Semiconductors's 16550. There are more recent
versions of this chip which could easily work at 800 kbauds but they
cost 1 or 2 dollars more per piece, a tremendous saving for PC
manufacturers.
What really limits analog modems (the application above has no modem of
course) is the frequency dependent attenuation over analog telephone
lines: no way to run faster than 56kbauds with such technology at
distances such as from homes to the nearest phone exchange (for
telephone companies which have digital connections from exchange to
exchange).
Enjoy your modem, nevertheless.
09/12/2010 03:44 PM, Jonathan E. Brickman wrote:
Now that's interesting. 'wvdialconf' worked delightfully. And
'minicom' is also working well now, after I created the /dev/modem
symlink.
I was shocked to see 'wvdialconf' set the serial port at 460800. Now
I see why I saw it written that these modems might work at less
latency than hardware modems. That's much higher than anything I ever
saw before in serial (or virtual serial, in this case, I guess).
RS-483 and other RS-232 derivatives do run at that speed and higher,
though, so I shouldn't be too urprised, and 16550A does contain
RS-483...hmmmmm...:-) Well, the time has largely past for such, but I
can dream.
Unless something invisible's wrong with the hardware, I'll expect it
to work now. Many thanks.
I might be motivated enough to make something simple and graphical.
Anyone know a really simple toolkit? I do little programming these
days, because I have come to resist delving into arcana, but perhaps I
can find a toolkit to make it easy enough to be worth the while.
By the way, Marv, POTS means "Plain Old Telephone System" *grin*
J.E.B.
Jon,
Most of us use wvdial. The setup is
# sudo wvdialconf
which should report finding the modem, and generate /etc/wvdial.conf
Edit it with
# gedit /etc/wvdial.conf
removing the ;< > symbols while putting in your personal info.
And add two lines
Carrier check = no
# is needed for modems using /dev/pts/N ports
Subsequent dialout is with:
# wvdial
I'm not familiar with POTS
MarvS
On Sat, Sep 11, 2010 at 5:46 PM, Jonathan E. Brickman
<jeb@xxxxxxxxxxxxxxxx> wrote:
Many thanks for the enormous work on the 'martian' driver; it is now
working well according the 'dmesg' et cetera. I'm not sure the best
way to
do a basic AT command query anymore (minicom doesn't seem to want to
run but
it does not seem to have been worked on very much), but I figure if the
driver says it's OK, I should probably be going to PPP anyhow. This
brings
me to my question: how in the world do you do PPP over POTS on Fedora
13?!!!??? I did a whole lot of searching for docs, found lots of
requests
but no info. Lots of things have changed in the ten years since I
last set
up PPP over POTS on Linux!!! I would love to either keep
NetworkManager or
wicd, but I thought I should consult wiser heads before moving on,
especially when the RT*M method did not come up with anything clear.
J.E.B.
