26 Nov
2006
26 Nov
'06
2:39 p.m.
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.
-Toth
26 Nov
26 Nov
2:45 p.m.
Toth,
On 11/26/06, Tothwolf <tothwolf at concentric.net> wrote:
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.
While I can't answer with the DEC spec, how about 'as long as you need
them to be for what you're doing'? I've never used an MMJ cable
longer than ten feet, myself.
Josef
--
"I laugh because I dare not cry. This is a crazy world
and the only way to enjoy it is to treat it as a joke."
-- Hilda "Sharpie" Burroughs,
"The Number of the Beast" by Robert A. Heinlein
10:04 p.m.
On Sun, Nov 26, 2006 at 01:39:32PM -0600, Tothwolf wrote:
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.
-Toth
The BC16E DECconnect MMJ Crossover came in several standard sizes
identified by the two-diget length following the part number. The most
common lengths seem to have been BC16E-02 (two-foot patch cable),
BC16E-05 (5'), BC16E-10 (10'), and BC16E-25 (25').
I keep meaning to buy some more, so please let me know if you're
interested in sharing!
-Seth
27 Nov
27 Nov
12:08 p.m.
Tothwolf wrote:
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.
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.
12:57 p.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
1:17 p.m.
Tothwolf wrote:
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? :)
I don't think that they're AMP-branded per se, but cables.com has MMJ
connectors for $0.19 qty 1. I usually buy about a hundred at a time.
Peace... Sridhar
1:50 p.m.
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.
Depends on where the equipment is located in relation
to each other. Longer cables will work in place of the shorter
ones, but you end up with a lot of extra cable to hide, which
will collect dust and generally get in the way.
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've had a lot of equipment destroyed by lightning over
the years. The damage goes from invisible (internal
problems in IC's), to the extremely visible (hole burnt
completely through circuit board and IC's missing,
except for some legs). Usually not worth fixing, because
many other components are likely to fail soon after
any repair.
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josefcub＠gmail.com -
kth＠srv.net -
ploopster＠gmail.com -
sethm＠loomcom.com -
tothwolf＠concentric.net