🚀 go-pugleaf

	Having finally gotten fed up with the spaghetti in our machine
room, I've decided to redo all the terminal wiring using telco-style
pushdown blocks.  For historical reasons, we've got about 100 lines coming
into the machine room for 40 ports -- some are lines run to offices in
anticipation of future needs, some are lines no longer in use but which
might be needed again some day.

	What I want to do is set up a panel with a termination for each
port on one side and a termination for each external line on the other and
patch between them as necessary.  Since patching won't be frequent, I don't
need anything as fancy as plug-in patch panels; re-doing a punchdown jumper
will be easy enough.  The problem is that we've got miles of Belden 8723
(stranded shielded twisted pair) all through the building and I understand
that punchdown blocks are made to only work with solid wire.  Has anybody
tried using stranded wire in punch-down blocks?  Will it work?  The last
thing I want is to have hundreds of connections start to work themselves
loose in a year or two.

	We wire our runs like this:

          1 ----------------------------------- N/C
 Computer 2 ----------------------------------- 3     Terminal
   End    3 ----------------------------------- 2       End
          7 =================================== 7

	The frame ground is connected to the shield only at the computer
end and xmit and rcv are each twisted with a signal ground (we run 9600
over 250+ feet, and one 19.2k line over about 100 feet with no problems, so
I must be doing something right).  If the 20-30 feet between the patch
panel and the computer is 8723, as is the external line, will I loose much
if I make the patch between them plain unshielded solid phone wire?  Do
impedance mismatches make any difference at these rates, or should I just
be worried about how many feet of wire are exposed to EMI, or are the noise
margins good enough that I shouldn't even worry about that?  I suppose it's
obvious, but I guess I should mention that we're talking RS-232.
-- 
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016

"you can't spell deoxyribonucleic without unix!"