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 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 > Reply-To: Main PLUG discussion list > > To: plu >> Main PLUG discussion list > > 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 > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us > To subscribe, unsubscribe, or to change your mail settings: > http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us > To subscribe, unsubscribe, or to change your mail settings: > http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss >