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1 Reply Latest reply: Jan 23, 2011 2:00 PM by jschellSomeoneStoleMyAlias RSS

Javax.comm speed

833567 Newbie
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Hi all,

i have a strange problem in using the javax.comm api.
The serial port could be opend without any problems (usb to serial-adapter), switching ports manually is also no problem.

Now two lines from an external machine are connected to this usb adapter. The external machine switches line 1 to high, line 2 to high, waits a short time, switches line 1 to low, line 2 to low and so on.

During this time i can see on the oscilloscope, that if line 2 is high, line 1 is also high, without any doubt, no errors from outside, the voltage levels are really okay.

Now i try to read these signals on the machine, that uses the usb adapter and javax comm, but i have the problem, that if i let run a program, that only prints out the state of line 1 and line 2, i really get the state, that line 2 has another level than line 1.

Can i do any flushes or something like that ?

Can anyone help me ?

  • 1. Re: Javax.comm speed
    jschellSomeoneStoleMyAlias Expert
    Currently Being Moderated
    A interface expects a minimal protocol implementation. 0 So for example a serial port, the hardware itself, expects a certain rate at which high/lows arrive. If the signal is outside of the expect range then the behavior is indeterminate.

    I would expect that is your problem.

    And just in case the signals are interpreted digitally, so you are never going to get different 'levels' (if that is what you meant.)


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