27 Feb
2002
27 Feb
'02
8:35 a.m.
Robert F Schaefer wrote:
Apparently the thought was to sell/bundle the 90 degree cable, to
force the
purchaser to `upgrade' to the straight cable when
it was necessry
to plug
in more than one SCSI device. I cursed it soundly when
I realized
it
obstructed the pass-thru connector on the back of the
TK50 I have.
As all
my other SCSI toys have the HD connectors, I might have
to end up
getting a
50-pin centronics-like :) M-F cable to connect things.
Sometimes the 90-degree cable works best and sometimes
the straight one works best. The 90-degree ones work
nicely at the back of a VS4000 ... not so much
spce is needed at the back of the box (vents
are at the sides!).
Same deal goes with the 90-degree vs straight
ethernet connectors.
Horses for courses.
Antonio
27 Feb
27 Feb
8:01 p.m.
Within the forseeable future I will be doing some cabling.
Most of this will be external to connect terminals to
DEC terminal connectors and some internal ribbon stuff.
Are most of you handling the former by using patch
cords and then attaching the appropriate modular
adapter (rearranging the pinouts if necessary)?
Or using a crimper and building yourself?
I need to do that with a MicroVAX II and vt220.
This requires a DB9 and DB25 with a DEC pinout.
I already have the pinouts, just need to go to
the store and buy it.
Additionally, I will taking the RX50 out and replacing
it with a TK50. I will buy ~64cm (length of BA23 enclosure)
of 26 way flat ribbon cable and 2 IDC connectors. As far as
I know this is all I need. Any additional advice for
this procedure? I already have the M7546 (Tape controller).
On Wed, Feb 27, 2002 at 02:35:48PM -0800, Carlini, Antonio wrote:
--
Bill
Amsterdam, NL
Robert F Schaefer wrote:
Apparently the thought was to sell/bundle the 90 degree cable, to
force the
purchaser to `upgrade' to the straight cable
when it was necessry
to plug
in more than one SCSI device. I cursed it soundly
when I realized
it
obstructed the pass-thru connector on the back of
the TK50 I have.
As all
my other SCSI toys have the HD connectors, I might
have to end up
getting a
50-pin centronics-like :) M-F cable to connect
things.
Sometimes the 90-degree cable works best and sometimes
the straight one works best. The 90-degree ones work
nicely at the back of a VS4000 ... not so much
spce is needed at the back of the box (vents
are at the sides!).
Same deal goes with the 90-degree vs straight
ethernet connectors.
Horses for courses.
Antonio 
9:12 p.m.
On Thu, 28 Feb 2002, William S. wrote:
Are most of you handling the former by using patch
cords and then
attaching the appropriate modular adapter (rearranging the pinouts if
necessary)? Or using a crimper and building yourself?
What you should be concerned about is shielded vs unshielded cable.
Shielded round cable with D-Sub type connectors will be more immune to RF
noise, and less likely to generate the same. A twisted pair or flat silver
satin cable with RJ-45 (8 conductor) or RJ-14 (6 conductor) connectors
isn't shielded, and most RJ-45/RJ-14 to D-Sub adapters are also not
shielded. I've made up both types of cables, but I usually use shielded
cables for connections between equipment since my systems live in an
residential neighborhood.
Additionally, I will taking the RX50 out and replacing
it with a TK50.
I will buy ~64cm (length of BA23 enclosure) of 26 way flat ribbon
cable and 2 IDC connectors. As far as I know this is all I need. Any
additional advice for this procedure? I already have the M7546 (Tape
controller).
If you don't have an IDC press and this is the first ribbon cable you've
ever made, buy at least 2.5x the amount of cable you think you'll need,
and at least twice as many connectors. IDC connectors are somewhat fragile
when pressing onto ribbon cable, and without the proper press, you end up
damaging at least one before you get the technique down. Ribbon cable and
IDC connectors are both inexpensive, so it would be good idea to have some
extra. A vice and some small blocks of wood can press IDC connectors onto
ribbon cable in a pinch. Don't try to press the connector on by hand, it
won't work, and you'll break the connector. Also, don't use scissors to
cut ribbon cable. It frays the ends of the wire, and can short out the
conductors. If you don't have a flat cable cutter, (carefully) use a metal
straight-edge and an X-Acto knife to cut the cable.
-Toth
9:26 p.m.
By shielded do you mean CAT5 cable? I was planning on
using that. Speaking of which, is there a proper
color to use? ie) grey, red, blue? This will only
be a home setup but was wondering if there is an
official color code.
On Thu, Feb 28, 2002 at 05:12:40AM -0600, Tothwolf wrote:
<<snip>>
What you should be concerned about is shielded vs
unshielded cable.
Shielded round cable with D-Sub type connectors will be more immune to RF
noise, and less likely to generate the same. A twisted pair or flat silver
satin cable with RJ-45 (8 conductor) or RJ-14 (6 conductor) connectors
isn't shielded, and most RJ-45/RJ-14 to D-Sub adapters are also not
shielded. I've made up both types of cables, but I usually use shielded
cables for connections between equipment since my systems live in an
residential neighborhood.
<<snip>>
--
Bill
Amsterdam, NL
10:16 p.m.
On Thu, 28 Feb 2002, William S. wrote:
On Thu, Feb 28, 2002 at 05:12:40AM -0600, Tothwolf
wrote:
Cat5 (category 5 rated) cable is more appropriately called UTP (unshielded
twisted pair) cable. UTP cable is not shielded, and for serial
applications, the category rating isn't very important. Keep in mind that
category '5e' cable is much more difficult to work with compared to
category 5/4/3 if you are planning to install RJ45 connectors yourself,
due to molded pairs. As far as wire colors go, UTP cable has a standard
color code for the individual pairs, but the pinout varies depending on
the application for the cable. I'm not aware of any "standard" color code
for UTP cable when it is used for serial applications.
-Toth
What you should be concerned about is shielded vs
unshielded cable.
Shielded round cable with D-Sub type connectors will be more immune to RF
noise, and less likely to generate the same. A twisted pair or flat silver
satin cable with RJ-45 (8 conductor) or RJ-14 (6 conductor) connectors
isn't shielded, and most RJ-45/RJ-14 to D-Sub adapters are also not
shielded. I've made up both types of cables, but I usually use shielded
cables for connections between equipment since my systems live in an
residential neighborhood.
By shielded do you mean CAT5 cable? I was planning on using that.
Speaking of which, is there a proper color to use? ie) grey, red,
blue? This will only be a home setup but was wondering if there is an
official color code. 
28 Feb
28 Feb
5:48 a.m.
It was thus said that the Great William S. once stated:
By shielded do you mean CAT5 cable? I was planning on
using that. Speaking of which, is there a proper
color to use? ie) grey, red, blue? This will only
be a home setup but was wondering if there is an
official color code.
Do you mean for the outside sleeve, or the individual wires in the cable?
For the outside, there is no real standard color that I'm aware of, although
there is a standard ordering for the wires when crimping (I think it goes
orange, green, brown, blue (solid followed by white and color) but don't
quote me on that---it's been awhile since I've crimped CAT5 network cables).
But for a regular CAT5 cable, as long as you use the same order for each
end, it'll work fine.
-spc (I don't remember the ordering for a cross-over cable though)
1:58 a.m.
On Thu, 28 Feb 2002, Tothwolf wrote:
conductors. If you don't have a flat cable cutter,
(carefully) use a metal
straight-edge and an X-Acto knife to cut the cable.
I use a meat cleaver and hardwood cutting board. :)
Seriously, if the blade is sharp (really sharp, like shaving grade)
and you're good enough to part chicken without splintering the bone, it's a
cleaner cut than a "draw" cut.
Doc
3:42 a.m.
Tothwolf wrote:
If you don't have an IDC press and this is the
first ribbon cable you've
ever made, buy at least 2.5x the amount of cable you think you'll need,
and at least twice as many connectors. IDC connectors are somewhat fragile
when pressing onto ribbon cable, and without the proper press, you end up
damaging at least one before you get the technique down. Ribbon cable and
IDC connectors are both inexpensive, so it would be good idea to have some
extra. A vice and some small blocks of wood can press IDC connectors onto
ribbon cable in a pinch. Don't try to press the connector on by hand, it
won't work, and you'll break the connector. Also, don't use scissors to
cut ribbon cable. It frays the ends of the wire, and can short out the
conductors. If you don't have a flat cable cutter, (carefully) use a metal
straight-edge and an X-Acto knife to cut the cable.
Jerome Fine replies:
I thought I might add a few observations about the cables I have made.
(a) I have worked only with 50-pin flat SCSI cables and the 20-pin/34-pin
cables for MFM drives or floppy drives
(b) I don't have an IDC press - I use a small vice with opposing heads
that are about 2 1/2" * 1/2" - I have never bothered to add wooden
blocks - the vice heads are undamaged and quite flat
(c) I usually work with USED materials, i.e. not only old cables, but also
salvaged header parts (connectors)
(d) I use a very sharp scissors to cut the cables - when I inspect the
cut cable end with a jeweller's loop, I can't remember when I have
found any frayed ends or shorts between the different strands
(e) Normally, I inspect the header parts (connectors) match-up to the
cable with a magnifying glass (sometimes even a jeweller's loop) just
before the parts are put between the heads of the vice
On a VERY few occasions, I have jumpered some of the strands
to each other when that was required. In a BA23 box with only
4 button switches, the READY line and WRITE PROTECT line
needed for a second MFM hard drive (RD52) were cut out with a
small X-Acto knife. Then I used the X-Acto knife to bare the
corresponding strand from the first hard drive. I then soldered the
two strands for the second hard drive to the corresponding strands
for the first hard drive. While I could not remove the WRITE
PROTECT status for both drives except by a re-boot, at least
WRITE PROTECT was available for both drives when required.
Toth, the above are not contradictions of your advice, just my
experiences when I did not know how to do anything at all and
used trial and error.
4:30 a.m.
Really, with care, you can do it with a vise with
rubber/wood pads for the jaws. Just keep everything
perpendicular. And watch the orientations on pin 1.
The connectors will definitely not "recycle" reliably
without extreme care. Most connectors will click when
100% tight. Don't undertighten, but don't overtighten
either on the vise.
Gotta tell a funny story: I was working for a computer
company in 1980 when I was to install the company's
first 5M Shugart ST-506 HDD in the country at a car
dealship in Nowhere, Wisconsin (100+ miles from the
office). Being a new piece of equipment, I had no
spares. So, I go up there and what was delivered there
didn't work. I examined the cabling and determined
that the cabling was made backwards. So, I call up the
home office in California. Talked to a French engineer
who obviously thought that I was an idiot about the
cable. He told me to take the cover of the drive off.
Naturally, I knew that he meant the drive subassembly
housing cover, but I waited a few moments, and then
told him that I got the cover off, was looking at the
drive spinning and head moving, and what should I do
now (remember, at the time, this was USD$500 OEM in
1980 dollars, and the drives were on serious
allocation). All I heard was "merde" "merde".
After he calmed down, he agreed with me that the
connector was backwards.
I spoke to the dealership owner at length about the
delicacy of the drive mechanism. No jarring the table,
no dropping, no vibration, don't forget to park, and
so on.
So, in the same breath, I asked him for a rubber
mallet to fix the cable with.
I did recycle the connector end in the field with a
rubber mallet, a pair of pliers, and my shoe heel as
an anvil! The locks on the connector were broken, but
as long and no one went inside the box it was OK. The
dealer got a good laugh out of the whole thing. As far
as I know, it worked until the equipment was
obsoleted.
--- Jerome Fine <jhfine(a)idirect.com> wrote:
__________________________________________________
Do You Yahoo!?
Yahoo! Greetings - Send FREE e-cards for every occasion!
http://greetings.yahoo.com
Tothwolf wrote:
If you don't have an IDC press and this is
the
first ribbon cable you've
ever made, buy at least 2.5x the amount of cable
you think you'll need,
and at least twice as many connectors. IDC
connectors are somewhat fragile
when pressing onto ribbon cable, and without the
proper press, you end up
damaging at least one before you get the
technique
down. Ribbon cable and
IDC connectors are both inexpensive, so it would
be good idea to have some
extra. A vice and some small blocks of wood can
press IDC connectors onto
ribbon cable in a pinch. Don't try to press
the
connector on by hand, it
won't work, and you'll break the
connector. Also,
don't use scissors to
cut ribbon cable. It frays the ends of the wire,
and can short out the
conductors. If you don't have a flat cable
cutter,
(carefully) use a metal
straight-edge and an X-Acto knife to cut the
cable.
Jerome Fine replies:
I thought I might add a few observations about the
cables I have made.
(a) I have worked only with 50-pin flat SCSI cables
and the 20-pin/34-pin
cables for MFM drives or floppy drives
(b) I don't have an IDC press - I use a small vice
with opposing heads
that are about 2 1/2" * 1/2" - I have never bothered
to add wooden
blocks - the vice heads are undamaged and quite flat
(c) I usually work with USED materials, i.e. not
only old cables, but also
salvaged header parts (connectors)
(d) I use a very sharp scissors to cut the cables -
when I inspect the
cut cable end with a jeweller's loop, I can't
remember when I have
found any frayed ends or shorts between the
different strands
(e) Normally, I inspect the header parts
(connectors) match-up to the
cable with a magnifying glass (sometimes even a
jeweller's loop) just
before the parts are put between the heads of the
vice
On a VERY few occasions, I have jumpered some of the
strands
to each other when that was required. In a BA23 box
with only
4 button switches, the READY line and WRITE PROTECT
line
needed for a second MFM hard drive (RD52) were cut
out with a
small X-Acto knife. Then I used the X-Acto knife to
bare the
corresponding strand from the first hard drive. I
then soldered the
two strands for the second hard drive to the
corresponding strands
for the first hard drive. While I could not remove
the WRITE
PROTECT status for both drives except by a re-boot,
at least
WRITE PROTECT was available for both drives when
required.
Toth, the above are not contradictions of your
advice, just my
experiences when I did not know how to do anything
at all and
used trial and error.
6:50 a.m.
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27 Feb
27 Feb
9:40 p.m.
----- Original Message -----
From: "Carlini, Antonio" <Antonio.Carlini(a)riverstonenet.com>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, February 27, 2002 05:35 PM
Subject: RE: DEC BC09J cable
<snip>
Sometimes the 90-degree cable works best and sometimes
the straight one works best. The 90-degree ones work
nicely at the back of a VS4000 ... not so much
spce is needed at the back of the box (vents
are at the sides!).
Same deal goes with the 90-degree vs straight
ethernet connectors.
Yes, it was just a minor rant about the wrong cable shipping (I assume) with
a VS3100 w/ TK50. I even tried lengthening the 90 degree connector with a
passthru SCSI terminator, but with the bus double-terminated it didn't see
the CDROM. :( I haven't had a chance to get the correct cable either.
Horses for courses.
Antonio
Bob
10:23 p.m.
On Thu, 28 Feb 2002, Robert Schaefer wrote:
From: "Carlini, Antonio"
<Antonio.Carlini(a)riverstonenet.com>
A 90-degree cable would be very useful for a BA213 chassis, since there is
a cover over the bulkhead panel. I have a brand new SCSI kit for a BA213
put away somewhere for the day I find a BA213 housed MicroVAX.
-Toth
Sometimes the 90-degree cable works best and
sometimes
the straight one works best. The 90-degree ones work
nicely at the back of a VS4000 ... not so much
spce is needed at the back of the box (vents
are at the sides!).
Same deal goes with the 90-degree vs straight
ethernet connectors.
Yes, it was just a minor rant about the wrong cable shipping (I
assume) with a VS3100 w/ TK50. I even tried lengthening the 90 degree
connector with a passthru SCSI terminator, but with the bus
double-terminated it didn't see the CDROM. :( I haven't had a chance
to get the correct cable either.
11:13 p.m.
A 90-degree cable would be very useful for a BA213 chassis, since there
is a cover over the bulkhead panel. I have a brand new SCSI kit for a
BA213 put away somewhere for the day I find a BA213 housed MicroVAX.
I don't have a BA213 chassis to look at, but I don't think this particular
cable would help-- the 90 degree connector is on the centronics-line end,
the other end is the special end that only fits a few models of
VAXstations. Maybe this isn't the same cable that every one else is
talking about. I do have some right-angle AUI cables and printer cables,
they are nice to have from time to time.
-Toth
Bob
8285
days inactive
8286
days old
12 comments
9 participants
participants (9)
-
Antonio.Carlini＠riverstonenet.com -
ard＠p850ug1.demon.co.uk -
doc＠mdrconsult.com -
jhfine＠idirect.com -
rschaefe＠gcfn.org -
sloboyko＠yahoo.com -
spc＠conman.org -
tothwolf＠concentric.net -
wilby98＠yahoo.com