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Re: [linux] Re: The "good" USB to RS-232 Serial converter

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  • ed
    ... Thinking about it, I ve not even heard the word plotter for many years. Then again, I ve not heard anyone mention Auto/turbo cad for a long time, other
    Message 1 of 6 , Jun 21, 2013
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      On Fri, Jun 21, 2013 at 09:02:10AM -0000, thad_floryan wrote:
      > --- In linux@yahoogroups.com, ed <ed@...> wrote:
      > > On Thu, Jun 20, 2013 at 06:25:43PM -0700, Thad Floryan wrote:
      > > > Many devices one might wish to use with one's Linux computer(s) do
      > > > their communition over an RS-232 serial line and a problem today is
      > > > that most if not all new desktop and laptop systems no longer have
      > > > a built-in serial connection.
      > >
      > > Often the serial is a last resort when other means of connectivity fail.
      > > It's sad that the serial port is disappearing from devices.
      >
      > The official spec for RS-232 serial (unbalanced lines) is 50 feet.
      >
      > One evening about 35 years ago, my best friend who then worked at HP
      > Labs in Palo Alto (later Nokia R&D and now Cisco) and I were at HP Labs
      > because he wanted to show me the original prototype of the waterfall
      > plotters (1000g acceleration, uranium-glass tip for its hardness, and
      > it'd do the entire test plot in about 2 seconds whereas all other such
      > plotters in the world would take 20 to 50 minutes to do that plot). I
      > noticed a 5000 foot spool of Belden 9-wire for RS-232 sitting over in
      > a corner and we decided to run a test over that 5000 feet. Long story
      > short, it worked, but the waveform on an oscilloscope was literally an
      > engineer's worst nightmare. That test showed, however, the robustness
      > of RS-232 which to me was very impressive. I have so many RS-232
      > things here at home I have RS-232 for many desktops via a PCIex1 card
      > and also Ethernet:RS-232 "terminal servers", for example:

      Thinking about it, I've not even heard the word plotter for many years.
      Then again, I've not heard anyone mention Auto/turbo cad for a long
      time, other than when I try to talk to people about coop designs, but
      that's so off topic.

      > http://thadlabs.com/PIX/EQ6_Ports_on_computer.jpg 192kB
      > http://thadlabs.com/PIX/EQ6_Syba_RS-232_PCIe_x1.jpg 135kB
      > http://thadlabs.com/PIX/Etherlite_EL-2.jpg 116kB
      >
      > Kinda weird operating that terminal server with its 10BASE-T when my
      > LAN and WAN connections are gigabit. :-)

      Its not uncommon to find devices like these in racks as standard

      <http://www.lantronix.com/device-networking/external-device-servers/eds16pr_eds32pr.html>

      > My several astronomy-related Linux laptops are all Dell Latitudes (the
      > business-level not the consumer crap) which have one RS-232 port both
      > on the laptops and on their docking stations. Comes in handy when I
      > want to control the scopes in the backyard from inside my office on a
      > cold Winter's night. :-)

      I found this in the e5430, to my amusement,

      <http://www.usenix.org.uk/content/dell_latitude_e5430.html>

      There was also a little easter egg on the sun disk caddy:

      <http://www.usenix.org.uk/content/sun_t5240_bracket.html>

      > It's going to be a long time before RS-232 goes away. In case you are
      > not aware, just about every oil pump (the birdlike-silhouette-looking
      > device that pumps crude oil out of the ground) uses RS-232 both for
      > its control and its data reporting. One of my customers in Texas took
      > me on a tour of his "facility" and that's when I saw the RS-232 there.

      Serial is very reliable, we use it all the time here, I use it mostly
      when doing hardware changes or firmware upgrades. Not really something
      that I would like to be without. The thing that saddens me is that
      people want serial for remote access, yet the portable devices appear go
      without. I have been in a situation before where I am on site with a
      laptop, with a USB serial connector but no driver as the laptop I was
      sent with was windows based. That was two employments ago though.

      --
      Best regards,
      Ed http://www.s5h.net/
    • Doug
      ... /anip/ ... /snip/ That s because all the mechanical engineers are using 3-d Cad programs now--and have been for at least 15 years. When I was still
      Message 2 of 6 , Jun 21, 2013
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        On 06/21/2013 06:24 AM, ed wrote:
        > On Fri, Jun 21, 2013 at 09:02:10AM -0000, thad_floryan wrote:
        /anip/

        > Thinking about it, I've not even heard the word plotter for many years.
        > Then again, I've not heard anyone mention Auto/turbo cad for a long
        > time, other than when I try to talk to people about coop designs, but
        > that's so off topic.
        /snip/

        That's because all the mechanical engineers are using 3-d Cad programs
        now--and have been for at least 15 years. When I was still working--I'm
        an electronic engineer--I used AutoCad all the time to layout pcb
        designs. (The microwave simulator would output dxf files that A/C could
        import.) After importing the microwave circuits, I'd add the peripherals
        via AutoCad. That was for breadboarding. When the design was production
        ready, it would go to a "designer" who converted the A/C file into some
        complicated pcb design that could handle multi layers and other
        fanciness--even tho I hadn't used (and could not use in the design)
        multi layers. I still have some versions of A/C on my pcs at home, but I
        haven't used one in years. I'm not sure I remember how! But for 2-d
        work, even multi-layer, you can't beat AutoCad, even tho it has a fairly
        steep learning curve. I was fortunate to learn on the job from an ME who
        (in those days) used it all the time himself.

        Breadboard pcbs (in those days) I could print on a LaserJet, and then
        get negs by a process camera, which we had on site. A tech would etch
        the pcb in the lab. Then the environment Nazis prevented us from using
        the chemicals, and everything had to be sent out. (I wonder what the
        pc labs do with the used-up chemicals?)

        Oh--plotter? Our PC designers had an HP plotter that could produce
        E-size output, in color, if required. But that was just for schematics
        and mechanical layouts. All pcbs went direct to the fab as Gerber plot
        files. I wonder if they still actually make paper prints? I can't
        imagine trying to deal with a complicated schematic on a computer
        screen, and I can't imagine doing assembly work from a screen either.

        --doug



        --
        Blessed are the peacemakers..for they shall be shot at from both sides.
        --A.M.Greeley
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