OK, let me see if I have this right...

You use the center tap on the "OUTPUT" side of the transformers, for
DC.

(This creates feedback through the secondary coil, but also acts as the
"Center" for it, essentially biasing it rather than saturating it.)

You put your "DATA LINE" and "CLOCK" line through the "Primary" thus
causing them to bias the basic OUTPUT voltage up and down. Since they
are on the primary, they are supposedly isolated from the DC voltage...

This creates a combination DC/AC signal referenced to the DC voltage...

Um.... it seems to me, you need 5 wires unless you couple the "Low" end
of the signal to the ground....

two for each signal, and one for ground...

on the other hand, if you ground the one secondary, and output off the
center tap, and the high line you could get by with three wires...

is that right?

                                GREY

GRAEME SMITH                         email: grysmith@freenet.edmonton.ab.ca
YMCA Edmonton

Address has changed with little warning!
(I moved across the hall! :) )

Email will remain constant... at least for now.


On Sun, 31 Jan 1999, dave vanhorn wrote:

> Use two pairs, and two 1-1 transformers, centertapped. Put the DC in on the
> center taps, and run clk on 1 xfmr and data on the other, or go async 422.
> We did this commercially, and it worked quite well. The DC through the
> transformers cancels out, so you don't saturate the core. If you multidrop,
> your "feeder" may need to get large, or you can do a passive or active
> repeater that powers a segment.
>