Re: OT: Windows serial port sniffing

Sorry for the delay, but I had a meeting to attend.

Eric is absolutely correct about the need for a voltage divider.
You will need to determine that the output of your system is not ging to
overwhelm things.

The article I had in mind is calling for an 1/11 divider.

Electronic Circuits for the Evil Genius by Dave Cutcher

http://www.books.mcgraw-hill.com/authors/cutcher


There you will find the Windoze program Winscope 2.51

The black wire will go from your ground to the base portion of the audio
plug. Use a 100 ohm resister to bridge the black wire to the red wire
which goes to the tip.

>From the junction of the red wire and the 10 ohm resister connect a 1000
ohm resister. The other end of the resister goes to your connection.

I accept no responsibility for any damage to equipment for any
miscommunication regarding the construction of this circuit.

Cutcher says your sound card will not take more than two volts.
The divider will drop a nine volt signal to .8 volts.

I no longer have a Win machine so I have not been able to use this
circuit. I hope someday to write such a program in Linux, but if someone
else gets there first it will not break my heart

Harold

-----Original Message-----
From: Eric Cope <eric.cope@gmail.com>
Reply-To: Main PLUG discussion list
<plug-discuss@lists.plug.phoenix.az.us>
To: iscreamkid@gmail.com, Main PLUG discussion list
<plug-discuss@lists.plug.phoenix.az.us>
Subject: Re: OT: Windows serial port sniffing
Date: Mon, 18 Aug 2008 10:50:02 -0700

be careful at connecting serial wires +-15v to audio inputs... Unless
you know what a voltage divider is...
A divide by 10 sounds correct, but I am not sure...
http://www.physicsforums.com/showthread.php?t=131827

I recall being able to control some of the handshake wires in a serial
connection in a windows program in a manner that you describe, but that
was a few years ago... There should be some tutorials on Google...

http://msdn.microsoft.com/en-us/library/ms810467.aspx

Good luck,
Eric

On Mon, Aug 18, 2008 at 10:39 AM, koder <hmichels01@earthlink.net>
wrote:

        There is a program which I am pretty sure is free that will look
        at the
        voltage levels on the serial port and display them as a graphic
        display.
        it was intended to allow you to use the serial port as a
        voltmeter.

        The program is made available by the man who writes the Evil
        Genius
        series of hardware books.

        I am not able to give more information at this time.

        What you do is run a wire across a resister that drops the
        voltage to
        audio levels. Plug the wire into the line in on your sound card.
        The
        program seed the analog signal and displays it on the graph.

        Harold

        -----Original Message-----
        From: Charles Jones <charles.jones@ciscolearning.org>
        Reply-To: Main PLUG discussion list
        <plug-discuss@lists.plug.phoenix.az.us>
        To: plu >> Main PLUG discussion list
        <plug-discuss@lists.plug.phoenix.az.us>
        Subject: OT: Windows serial port sniffing
        Date: Mon, 18 Aug 2008 08:46:49 -0700

        This is technically a windows question, but I thought I would
        ask here
        anyway, because many of us were hacking before MS-windows
        existed, and
        also ran various versions of MS-windows in our time (which is
        why we
        love Linux so much now!) and have dealt with serial ports from
        dealing
        with modems and the like. I figured I would tell you all about a
        minor
        problem I am thinking of tackling, and see if you had any
        suggestions.

        I'm dealing with an RFID badge-access system that uses
        windows-based
        administration software. Basically some software that runs on
        windows,
        using an mssql db, and communicates with the hardware via the
        serial port.

        The software has a function to send a timed pulse to unlock a
        door(s)
        for X number of seconds.  I'm looking for a way to do the same
        thing,
        but from another machine so that I can use a script or even a
        CGI to
        control the door. Yes, I realize this opens us up to someone
        "hacking"
        their way into the office, but we also have a security system
        and if
        they have root on our servers then we have bigger problems :)  I
        digress...

        I have some long ago experience in serial port programming. In
        school I
        wrote a voicemail system in Turbo Pascal (heh), that controlled
        a POTS
        line via a relay that I connected to the serial port. I remember
        studying the serial port pinouts and figuring out how to control
        the
        voltage level to each of the pins.

        That being said, I have several things I have to consider:
        * Is the door lock pulse simply a voltage level sent to the
        serial port,
        or is there some sort of protocol (an actual serial connection)
        between
        the computer and the hardware?
        * Is the signal being sent just a toggle, or a specific turn
        on/off events?

        I basically need a way to snoop the serial port to see what is
        being
        sent, but I'm not sure of the best way to do it.  If it is just
        voltage
        levels being sent to the hardware, I could do it with just a
        multimeter
        and figure out which pins it is activating.  However, if there
        is an
        actual serial connection (null modem or something) going on, it
        will be
        much more difficult to observe what data is being sent. I think
        also you
        can purchase an in-line dongle that has LEDs that will show the
        status
        of the data lines.

        I suppose one of the first things I could do is to just unplug
        the
        serial port, and try to use any functions that talk to the
        hardware.  If
        there is any data connection required, it should complain that
        it is not
        connected.

        Theoretically I could write a small a small C++, (or even Win32
        perl)
        daemon that would run on the winblows machine and provide a way
        to
        toggle the lock/unlock signal via a TCPIP connection. I may run
        into a
        snag where, if I remember correctly, if something has control of
        a
        serial port in Windows, no other process can open it.  Maybe I
        could do
        something sneaky like a Y-adapter and just send the signal from
        another
        machine altogether. I wonder if I would have to use some diodes
        to keep
        any voltage from one leg of the Y from traveling back to the
        other
        machines serial port...hmmm
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