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110RE: Ok Now What?

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  • Ian ZL1VFO
    Apr 1, 2006
      > Message: 15
      > Date: Fri, 31 Mar 2006 20:49:50 -0800
      > From: <scott@...>
      > Subject: RE: Ok Now What?
      >
      > Before the MAX232, actually.. it'll most likely be a 2N3904 with a pull up
      > to 5 volts, so that an input on the base pulls it low - same as the RX side
      > of the tracker itself. I'll come up with a schematic after I get the shells
      > and see what will fit.

      > Scott

      Well, since the MAX232 has 2 line drivers and 2 line receivers, all 4
      of which are inverters, couldn't you just use the 'spare' inverters
      to re-invert back to normal? I've done just that on my home made
      TinyTrak board - it's been working reliably for several years now.

      Let's see, looking at my notes for what I did, <rummage, rummage> the
      uController TxD line joined to the MAX232's pin11 (T1in),
      pin14 (T1out) to pin10 (T2in), pin7 (T2out) to the DB9 TxD.

      Going back the other way, DB9 RxD to pin8 (R2in),
      pin9 (R2out) to pin13 (R1in), Pin12 (R1out) back to RxD on the
      uController.

      I also have 2 rows of 4 jumper pins connected to this circuit, so I
      could jumper them either as 2 inverters in series (no inversion), or 2
      inverters in parallel (inversion) for each direction, depending on
      what was required at the time.

      I may be able to draw it out & post it in the files section, if
      anyone's interested.

      73,
      Ian ZL1VFO



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