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  1. robd2002

    Capturing and decoding encrypted serial data

    Mike, You are spot on about the magic box that extracts what it needs from a data stream without effect on the data. Sender and receiver are unaware of its presence. And yes, the box will not work in this new data path. My guess is that all of the data is encrypted, as the output is total...
  2. robd2002

    Capturing and decoding encrypted serial data

    Mac, Thank you for the reply and assessment of my abilities. The reality is that I'm about the only engineer at my company and have had to resort to professing my ignorance to the world out of sheer desperation - nobody here with whom to truly collaborate. That said, I have found an uncanny...
  3. robd2002

    Capturing and decoding encrypted serial data

    Mike, Thank you for the link and I agree the content is not suitable. I should not have included the acronym. I don't see any way to delete or edit the post as I surely would. The general question was how to go about decoding "dynamic" RS-232 serial communication. Regards, Rob
  4. robd2002

    Capturing and decoding encrypted serial data

    Hi, I've been asked to decode serial data passing between a point of sale system (fancy name for fancy cash register) and a gasoline fuel controller. Data typically consists of commands from the POS to the controller such as "what is your status", "you are auhorized to dispense fuel", "how...
  5. robd2002

    "sniffing" USB -

    Rob: 4. From PC1, print the same document as in step 1, except now the printer is connected to PC2. IR: OK, this is where you write a driver that spits the USB stuff you get from PC1 USB connection to the printer's USB connection Rob: Definitely over my head... Rob: 5. PC2 has software...
  6. robd2002

    "sniffing" USB -

    I'm familiar with Atmel's STK500 and the M128 processor. I've programmed it to measure a serial baud rate by clocking bit patterns (boss won't allow an oscilloscope - apparently likes things done the hard way). I could imagine capturing bits and making a lookup table instead of using a UART...
  7. robd2002

    "sniffing" USB -

    Dan: Are you trying to reverse engineer the printer's protocol? Rob: No, just capture some of the printed data, e.g. gallons of gasoline sold. Dan: Can you not simply ask the manufacturer for the protocol? Rob: My experience is that companies do not in general give away their secrets for...
  8. robd2002

    "sniffing" USB -

    Again, I appreciate the responses but none of you are telling me what I want to hear: Boss is asking for something impossible. Here is what Boss thinks can be done: 1. Start with PC1 connected to a printer. Print a document. 2. Disconnect the printer USB cable from PC1 and plug it into...
  9. robd2002

    "sniffing" USB -

    Hi IR, and thank you very much for the reply. Can you ballpark the effort level required, and is it realistic to think that an "all around type system engineer" who is OK at a bunch of things, knows enough to get himself into trouble and can usually get himself out of trouble, can tackle this...
  10. robd2002

    "sniffing" USB -

    Let me ask this: Let's assume I have pc1 connected to printer1 and pc2 connected to printer2. I know that if the printers are RS-232 serial, that the letter A will show up as 41h, whether or not the printers are Panasonic or Canon. Now let's move from 1980 to 2010 and upgrade to USB...
  11. robd2002

    "sniffing" USB -

    Mac, I sure appreciate the reply. So - it's feasible to make a piece of hardware that taps into the USB wires and can identify the text characters that are sent from a pc to a printer and store only those characters? I still cannot comprehend this. Nor can I thank you enough for talking to...
  12. robd2002

    "sniffing" USB -

    Hi, My company is pretty good at capturing RS-232 data between devices such as a point-of-sale system (cash register) and a serial printer, as long as we know the baud, parity, data bits, etc. My boss thinks I can do the same thing with a USB connection and I'm telling him I cannot. He thinks...
  13. robd2002

    Using a 120 VAC to 5VDC PS to sense 120 VAC - how to handle 277VAC?

    Hi, I needed to make a device to remotely detect whether or not a 120VAC circuit was live. We make a micro-based device that measures 0 to 5 VDC and converts it into a 10 bit number. Being in a rush and not wanting to screw around the best idea I could come up with was an open frame power...
  14. robd2002

    Is shielded cable necessary for a DC signal?

    Thank you Macgyver, itsmoked, VE1BLL, and zapped. I was able to visit the site and saw the difference between shielded and unshielded cable on an oscilloscope. Suffice it to say the difference was dramatic. I cannot say from where the noise originated, however. It sure seemed that it would...
  15. robd2002

    Is shielded cable necessary for a DC signal?

    My company makes a level sensing device that consists of a microcontroller board and a pressure transducer. The pressure transducer output ranges from 0.5 to 4.5VDC. The micro samples this line and sends the answer (10 bit number between 100 and 923) and from this and the density we figure out...
  16. robd2002

    underground conduit and direct burial in hazardous locations

    I just found this forum, and this is my first post. I am working on a fuel level sensor. The sensors are located in underground fuel tanks, and need to be connected to a panel inside the building. We have the sensor device ready and I need to specify how the wiring is to go from the tank to...

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