Look into CAN bus.
Even if you just consider mis-using the CAN transceivers and physical
layer, there's some really interesting possibilities.

On Sunday, October 22, 2017, David C Brown <dcb.home@gmail.com> wrote:

> I am playing about with some home automation.   I am looking towards a
> multimaster bus using a balanced transmitter and receiver such as RS485.
>
> Now I well understand how to handle the collision detection in software: =
I
> have done that in the past.  But in the past I used open collector TTL on=
 a
> single ended bus.
>
> That is not adequate in the present application because I am looking at
> distances up to 25 metres.(at a maybe 10KB)
>
> So the question is:  what chips can drive the balanced line yet survive
> contention without cooking
>
>
>
> __________________________________________
> David C Brown
> 43 Bings Road
> Whaley Bridge
> High Peak                           Phone: 01663 733236
> Derbyshire                eMail: dcb.home@gmail.com <javascript:;>
> SK23 7ND          web: www.bings-knowle.co.uk/dcb
> <http://www.jb.man.ac.uk/~dcb>
>
>
>
> *Sent from my etch-a-sketch*
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