On Aug 5, 2007, at 3:35 PM, David VanHorn wrote:

>> is this RS232 ring networking??
>
> Yes.
>
> Others have asked why not use 485 or 422, but sometimes what you have
> is 232 devices

The nice things about rs232 ring networks is that you can easily
(and cheaply) incorporate off-the-shelf consumer components like
a PC...

Have rs232 ring networks ever been formalized/standardized to
any extent (in a form useful/implementable on microcontrllers?)
The concept seems pretty common, but I don't think I've ever
seen libraries to support it in more detail.

Other points:

A normally-closed relay automatically takes "off" devices out
of the ring.

If the destination address is early in the packet, the delay
introduced at each node is reduced to a few character times
rather than a full packet time.

I think the obnoxious patents associated with token rings are
primarily concerned with the "token" part; a non-token ring
is probably patent-free.

BillW

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