27 Nov
2006
27 Nov
'06
9:57 a.m.
On Mon, 27 Nov 2006, Kevin Handy wrote:
Tothwolf wrote:
Ok. I'm just not sure what length are the most useful. I know the 12-15ft
cables always worked ok for me to connect systems/terminals/terminal
servers, but I'm just not sure if shorter cables would still work as well
length wise.
Lightning can do some pretty strange things. One of the more interesting
lightning damaged installations I found was where someone had run a
thicknet drop cable across a building roof. I have no idea what the person
responsible for that cable run was thinking.
I was thinking about putting together some
standard MMJ cables, but I
realized I didn't know what the standard lengths were. Can anyone tell
me which were the most common/useful lengths for the original DEC
cables? I've seen and use cables as short as 18" and as long as 50ft.
I've used a lot of them that were somewhere in the 12-15ft range, but
I'm not sure what length would be the most versatile.
The 5-6' cables were probably the most common, but you could go up to
about 300' if you ran it at a slow enough speed. Avoid outside runs as
much as possible (lightning damage can be very impressive). It really depends on the enviornment you are in on how
long your average
cable will be. If you are setting up a terminal room, you will probably
use short cables. If you are setting up in an office enviornment, you
will probably want to wire the walls, and place MMJ jacks on the wall.
Then you will need to have cables long enough to reach from the wall to
the desk (5' to 20'), depending on weither they are willing to have
their desk against the wall with the jacks.
I wired up a lot of long runs from a computer room to individual
offices, and you cannot get the cable through an existing wall with the
ends attached. They almost always get trashed on the way through the
wall, or get hung up on the way through.
I mainly just need to figure out what length will be the most useful for
equipment to equipment connections. None of these will be going in the
walls. Flat cord isn't rated for in-wall use anyway and in a commercial
building, the building inspectors would throw a fit.
I've also had a couple of people ask me off-list about making a few extra
MMJ cables since my initial email, so figuring out the most useful/common
length would help with those too. I think I only have 100ft or so of extra
cable on hand right now.
In any case, 6C flat cord is fairly cheap, but the plugs aren't (at least
the AMP brand ones anyway). Anyone happen to know a source for inexpensive
AMP brand MMJ plugs? :)
Later on, I used regular CAT-5 connectors on the
wallplates, and wired
cables up as CAT5-MMJ to the terminals. This allowed for later
transition to a network, as wll as using easier to find CAT5 wallplates.
I've done the Cat5 to MMJ cables lots of times myself. I've also used 6P6C
RJ11 to MMJ cables. I actually just made some more of those to use with
RJ11 to DE9F adapters, as I've yet to find genuine H8571-J adapters in
quantity at anything resembling a reasonable price.
-Toth