On 24 Aug 2003 08:38:01 -0700, jim rozen wrote:
In article , Gary Coffman says...
One final note. While you're just running one line to hook up one phone
now, the slick way to wire a house for phone and network cabling is to
have a central wiring closet and use star topology, home runs from each
phone outlet to punch down blocks in the wiring closet, instead of just
daisy chaining the wire from outlet to outlet. It will be much easier to
troubleshoot, modify, or expand at a later date.

Do those 'punch down' terminals *really* work? I know the
phone company uses them all the time, but I wonder if the
consumer grade ones are as good as the good stuff. I've
been wiring using old open style electronics terminal blocks
(the ones with screws, and the raised dividers between
contacts) and crimp-on lugs.

Yes, they really work. If you go into any large building, you'll
find thousands of connections made with punchdown blocks
for telephone and network connections.

As you may know, broadcast plants have traditionally used
"christmas trees" with solder down connections for audio
wire terminations connecting to major distribution points
like patch panels, routing switchers, and audio boards.

We faced a major hurry up renovation project in preparation
for the 96 Olympics and didn't have time to do all that tedious
soldering (thousands of connections). So we decided to try
punchdown blocks for low level audio wiring.

We weren't sure that it would hold up over time. We suspected
that oxidation would take its toll and cause noisy connections.
But it only had to work for a few weeks, then we could re-do it
properly at leisure.

Well here it is 8 years later, and we've yet to have a noisy
connection due to those punchdowns. They've also made
doing changes much quicker and easier. So at this point
I'd say they're as good as solder connections. Maybe
better, since cold solder joints have been a problem in
the past with the christmas tree method.

The manufacturers say that they work in the same way as
wirewrap. In other words, the terminals mechanically
cut into the wire and form a gas tight seal. So corrosion
can't start in the contact areas. Our experience using
them in a more critical area than phone wiring seems to
confirm this.

Note that you can only punch down *solid* wire. If you
need to terminate stranded wire to a punchdown block,
you need to use Scotchlock connectors. These are
plastic connectors which crimp onto the wire, then are
punched down onto the punchdown block's terminals.
They work fine too.

I don't know anything about "consumer grade" punchdowns.
We use the same type the phone company uses. Since we
buy from industrial electronics suppliers, I wasn't even aware
of any "consumer grade" punchdown blocks. Where do you
find those?

Gary