[ale] Winmodem

[Michael H. Warfield]

On Wed, Oct 13, 1999 at 08:34:18AM -0400, Sunil Patel wrote:
> I have a winmodem that I am trying to configure.  I have noted down the
> com port and IRQ it is uses from windows98.  I then used "setserial
> /dev/ttyS3 port 0xfff2 irq 10" to set IRQ and PORT.  Then when I run
> statserial /dev/ttyS3 command I get the output as follow:

	There is no support for LoseModems (aka HSP modems) in the Linux
kernel.  I saw in some messages a month or so ago up on the kernel mailing
list that someone was doing some work on one or two particular models of
losemodems.  One project was going to be full modem support and the other
project was going to be little more that a telephone audio board allowing
someone to use one of these stripped down bests as a voice mail board.
I haven't heard too much more about the former and it may not have progressed
very far.  I think the latter (the voice mail system) was pretty well on
the way, but that project didn't need to do nasy things like carrier decoding,
MNP logic, trellis modulation/demodulation or such.  All the later needed to
do was record a signal, play a signal, decode touch-tones (crude FFT works
there) and generate touch-tones (static patterns).

	Most losemodems are little more than DSPs (Digital Signal Processors)
on a board.  Some don't even have that.  They expect that all of the high
level logic is going to be done on the host.  It generally means that if
the host gets busy doing something and forgets to fill in the waveform
registers, you stop generating signal to the other end, it loses carrier
and drops you.  That's why losemodems have such incredibly poor reliability.
Distract the processor for a split second and your call is gone.

	HSP stands for "Host Signal Processing", so you can imagine the
implications.  Switch desktops in Enlightenment and your PPP connection
goes bye-bye while the screen is redrawing.

	It means that all the signal processing and logic that is in the
firmware of a "real modem" has to be buried in the kernel (and probably
one or more variations of it for every brand of modem supported) and all
the processing power that would be provided by the modem CPU now has to
be stolen REAL TIME from your main CPU.

> Device: /dev/ttyS3

> Signal  Pin  Pin  Direction  Status  Full
> Name    (25) (9)  (computer)         Name
> -----   ---  ---  ---------  ------  -----
> FG       1    -      -           -   Frame Ground
> TxD      2    3      out         -   Transmit Data
> RxD      3    2      in          -   Receive  Data
> RTS      4    7      out         1   Request To Send
> CTS      5    8      in          1   Clear To Send
> DSR      6    6      in          1   Data Set Ready
> GND      7    5      -           -   Signal Ground
> DCD      8    1      in          1   Data Carrier Detect
> DTR     20    4      out         1   Data Terminal Ready
> RI      22    9      in          1   Ring Indicator
> 
> However, when I use kpp to dial out.  It complains about not being able
> to find that device.  I tried using ppp scripts and the problem is
> same.  Should I try any other thing to make it work or does this mean
> that this winmodem will never work with Linux.  Your help will be
> appreciated.
> 
> --
> Thanks
> 
> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> 
> Sunil Patel                            BellSouth Telecommunications,
> Inc.
> DBA/Consultant                         Room 42P78
> email: yqrsdjl at snt.bellsouth.com       675 W. Peachtree St.
> Phone: 404-330-0570-W 404-221-1993-F   Atlanta, GA 30375

	Mike
-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw at WittsEnd.com
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