Hello,

< home automation & collision detection >

> If you're communication is half-duplex (which I guess is almost
> always the case when there are more than two nodes present), then
> you can use the Rx/Tx line for both communications and for
> arbitration. I can't go into details, but the gist of the idea is:
>
< lot's of idea's deleted >

Funny, I am working on a 485 bus system + protocol myself.

I figured out that I could use a half duplex bus ( 2 wires ) using
'switchable' transceivers ( Maxim has got some nice ones --> 1480 B )

The system works with one real master and 'psuedo' masters.

The master sends a broadcast or a direct request to one of the
slaves. If it is a broadcast the first slave will react and send
everything that might be important and will direct the second slave
to react. So basicly every point listens until it's adressed


Greetings, Gerard Gerritsen

ESD Electronics
Zwaansprengweg 20
7300 AE Apeldoorn, The Netherlands

email : gerritse@esd1.esd.nl
tel   : ++31-55-5499499
fax   : ++31-55-5427288