[RE-wrenches] RS485 wiring

[James Jefferson Jarvis]

RS-485 likes 120 ohm impedance cable. CAT5 is that and is generally a 
good choice for RS-485. RS-485 is differential signaling, so make sure 
that you use a single pair for A (D-) and B (D+). Your C (common) can be 
any other wire.

Belden Data-tuff is good stuff. Midnite Solar also apparently sells 600 
volt rated CAT5e.

Shielding is helpful, but probably isn't necessary.

Termination resistors are essential. Follow the manufacturers 
recommendations on these.

Good luck,

-James Jarvis
APRS World, LLC

On 5/14/2014 7:40 PM, william at millersolar.com wrote:
> Friends:
>
> I am connecting up some RS485 cards in Sunny Boys and Sunny Islands.
> Can I use Cat5 wire for that?  It is supposed to be shielded which
> standard Cat5 is not.  As usual, 600 volt rating would be preferable.
> Anyone have a source?
>
> Maybe this is another use for the Belden Data-tuff wire.  It is shielded
> if memory serves me correctly.
>
> Thanks for the input.
>
> William
>
> Gradient Cap_mini
> Lic 773985
> millersolar.com <http://www.millersolar.com/>
> 805-438-5600
>
>
>
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-- 
-James Jefferson Jarvis
APRS World, LLC
+1-507-454-2727
www.aprsworld.com