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RE: Re: CurrentCost serial cable wanted
Do the CC128 devices support multiple receivers ok? I presume the
wireless communication is one-way only?
Paul.
> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of Kevin Hawkins
> Sent: 05 March 2009 11:15
> To: ukha_d@xxxxxxx
> Subject: Re: [ukha_d] Re: CurrentCost serial cable wanted
>
> A PC RS232 port still requires the +/- 12V although most PC's I accept
> will work with 5V level signals. The serial cable from CC I assume
> level converts to near 12V.
>
> Stuart Poulton wrote..
> "A 3V signal will drop to 0.5v over 100 feet of cat5 cable "
>
> Ummm.. voltage drop over a length of cable is proportional to the
> current drawn. What did you use in your calculation ? That website is
a
> POE calculator.
>
> An RS232 input circuit on a PC can be very high impedence and hence
> create little current draw. In theory with zero current drawn the
> voltage will remain over infinite distance. However with an AC signal
-
> which a serial data stream is, then the capacitance is what creates a
> current impacting the voltage over distance and also related to
> frequency i.e baud rate. This causes the edges of the square wave
data
> to slope and characters to be misread.
>
> K
>
>
>
>
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