RE: Re: [Project] Lights was Foundations are in!

["Keith Doxey" <ukha@xxxxxxx>]

The reasons for RS485 are...
BiDirectional Comms over 2 wires
Balanced therefore 99.9% immune to interference
Multidrop - can support 32 devices on the bus
Single +5V supply

the reasons against RS232...
BiDirectional comms requires 3 wires Tx,Rx,GND
Not immune to interference
Point to Point only so would need 1 RS232 port per attached device
Requires +ve & -ve supplies

Keith

> -----Original Message-----
> From: Dr John Tankard [mailto:john@xxxxxxx]
> Sent: 02 June 2001 21:17
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Re: [Project] Lights was Foundations are in!
>
>
> --- In ukha_d@y..., "Keith Doxey" <ukha@d...> wrote:
> > Doing the lighting controller is fine by me.
> >
> Lots of snips.
>
> I agree with everything Keith has said.
>
> The prototype works, just the way keith described except i used rs232
> for the keypads.(only one per room). But i never used it. Actualy i
> have planking plates over the wall switch points. It gets all its
> instruction from my HV which has a extra serial port fitted.
>
> I supose it is going full circle, but i have no problem with that. I
> have done a lot of reading of the rabbit doc's now, still more to do.
> But I can see this room controler will spare capacity.
>
> My intro, did say we could use non tcp/ip local control.
>
> I like the idea, if we have cat5 in to switches we could change it
> tcp/ip later if a micro could do it.
>
> Sorry this is a short reply, banned from the pc, epod does not
> count ;-)
>
> John
>
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