Re: RS-232 converted to INFRARED

From: Michael (Micksa) Slade (micksa-news_at_knobbits.org)
Date: 10/29/04 

Date: Fri, 29 Oct 2004 11:17:13 GMT

On Thu, 28 Oct 2004 22:58:57 -0700, Scrotor wrote:

> Greetings!
>
> Ive been looking for schematic to do such and have questions on ones i
> have found.
>
> Heres one link im looking at:
>
> http://www.geocities.com/SiliconValley/Lakes/7156/laser6.jpg
>
> Im sorta new with the rs-232/serial communication, and am wondering
> about the CTS, RTS, ext... signals and how they dont seem to be used
> in the above schematic. Im assuming that CTS, RTS, ext.. are signals
> for the recipe of handshaking? What i have in mind is converting
> RS-232 from some 1489/1488 IC's to infared, then back to the RS-232
> level to feed to another combo of 1489/1488s. With all these different
> data lines, how are they combined for one signle infrared signal?
> would there have to be seperate IR leds for them?

They're not :)

They don't generally need to be.

The only real use for the other lines is for flow control, which can also
be achieved by sending certain data through the TX line (this is what
XON/XOFF, or software, flow control is).

If you *really* needed to have those lines in there, you'd have to use a
more complex solution that would involve multiplexing the other lines and
encoding them over a single stream. Which brings me to my next point

That circuit you've shown is overly simple. There's no modulation or
anything - the RS232 signals are simply turned into IR verbatim. This
means there's nothing to correct noisy reception, handle any kind of
interference from other IR sources, or recover from a communication break.
 For error *detection* at least, you could use parity over the serial
 line, but it won't be all that effective.

If you put it together into a real circuit, it may work but you might find
you'll have problems with it, e.g. it will only work with the lights off.

Having said all that, I wouldn't know where to find a better circuit :)

Anyone? 

-- 
My email address is "micksa@", not "micksa-news@".
VOTE [1] CAPITAL PUNISHMENT FOR SPAMMERS

Relevant Pages

  • Things pyrazo related...
    ... Introducing the Pyrazo circuit. ... This circuit induces a oscillation from a oscillation source to be ... through the primary of the pulse transformer. ... The device may be used to absorb or amplify signals from any signal ...
    (sci.energy)
  • Re: Proper use of differential outputs
    ... ie they tie one input line to their circuit 0V. ... this make use of differential signals pointless? ... Is there any reason not to use coax? ... I've considered and dismissed a couple of tricks I figured were too high risk like a notch filter to get rid of hum; but I've added a 300kHz linear phase filter to reduce HF fuzz, and an isolated power supply to get rid of earth loops. ...
    (sci.electronics.design)
  • Re: Need experts for vexing hum problem
    ... It would seem the star grounding has worked; the 120 Hz hum is now ... filament circuit isolated (and maybe tied to the chassis with a small RC ... What do you mean by ordering resistors to step down the scope probe ... You will be looking for signals in the microvolt ...
    (sci.electronics.design)
  • Re: LM13700 weirdness
    ... Jim Thompson wrote: ... The circuit works fine when powered off ... the gain should theoretically be zero... ... Signal comes in from the upper left and is divided down by the 100k and 100 ohm resistors, and the control signal comes in from the bottom right and is made into two signals 180 degrees out of phase for the two VCAs. ...
    (sci.electronics.design)
  • Re: LM13700 weirdness
    ... The circuit works fine when powered off ... With the control current input disconnected, ... the gain should theoretically be zero... ... Signal comes in from the upper left and is divided down by the 100k and 100 ohm resistors, and the control signal comes in from the bottom right and is made into two signals 180 degrees out of phase for the two VCAs. ...
    (sci.electronics.design)