Mail Archives: opendos/2001/04/25/10:49:12
wow, a mouthful. i am grateful to all.
-rich w
-----Original Message-----
From: Matthias Paul [mailto:Matthias DOT Paul AT post DOT rwth-aachen DOT de]
Sent: Tuesday, April 24, 2001 4:12 PM
To: opendos AT delorie DOT com
Subject: Re: PCI vs ISA
On 2001-04-24, Gregor J. Jones wrote:
> The chat program that is part of dospppd knows how to talk to a
> pci modem, so anything that can use an emulated ethernet pppd
> connection should work.
Regardless of the slot (PCI, ISA, PCMCIA/PC-Card), there are
several kinds of internal modems: controllerless modems,
soft-modems, non-8250/16x50 compatible "full" modems,
and 8250/16x50 compatible "full" modems.
Only modems of the fourth category can be used under any OS
without special driver software, modems of the first two categories
cannot be used on non-Windows OSes (because it would be
virtually impossible to write drivers for them), modems of the
third category may sometimes be used for some DOS applications,
if drivers would be available, that would allow to emulate a
network card (but you wonīt be able to use traditional terminal
applications which require the modem to be connected to
a COM port).
Although they may exist, I have yet to see a PCI modems of the
fourth category, and only few ISA modems fulfill these require-
ments these days. AFAIK, AMR??? modems are always soft-
modems, arenīt they?
At the moment I am aware of two types of external modems,
for serial communication via RS232C, and for USB.
Given all the problems with USB devices even under
Windows 9x, and the fact, that USB drivers for DOS
(and many other OSes) are almost non-existent, I always
recommend to only use internal modems that fully emulate
the register set of a 8250/16450/16550 UART chip, or even
better external serial modems connected to the PC via
RS232C. These modems can be used under any OS
(including DOS) without any problems.
Of course, these modems are more expensive than
"Winmodems", but, as always, you get what you pay for.
At least here in Germany it is easy to find serial modems,
but I understand that they have become quite rare in the
States, unfortunately...
> The only problem you might have is finding out the ioport and irq
> that the modem is using. My actiontec came with a diagnostic
> program...but there are others, one of which is by Ralf Brown
> (yes, he of the interrupt list, look on his web page).
These diagnostic tools are only useful if the modem is either
an external serial modem, or an internal modem emulating
the register set of the serial port.
You can also try my ACOM utility (available on my webpage).
It can automatically find serial ports on many non-standard
addresses and set up the BIOS equipment area so that the
ROM-BIOS, DOS, and DOS applications can make use of
the port. It can also help to logically swap ports, or to run
hardware diagnosis.
> Otherwise, I have not found any legacy dos software that will
> work. I used to use Wordperfect and Bananacom, but they are
> no-goes. They expect comports and ioports to be only in the old
> dos serial port ranges. I also tried the comport tools package,
> without success.
If an application uses DOS or the ROM-BIOS to communicate
with the serial port, or at least retrieves the I/O port address from
the BIOS equipment area, ACOM should be able to configure the
system so that you can use serial ports on non-standard addresses
without any backdraws.
If the application uses a hard-wired list of the four standard
addresses 3F8h/4, 2F8h/3, 3E8h/4, 2E8h/3, you will actually
have to use these addresses if the application does not allow
to specify the address of the I/O port.
Hope it helps,
Matthias
------------------------------------------------------------
Matthias Paul, Ubierstrasse 28, D-50321 Bruehl, Germany
<Matthias DOT Paul AT post DOT rwth-aachen DOT de> <mpaul AT drdos DOT org>
http://www.uni-bonn.de/~uzs180/mpdokeng.html
------------------------------------------------------------
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