Hi Jeff,
Right. That usually degenerates into using identical keyed
connectors.
It's worked (reasonably) for USB.
Also, you don't need a key if you can ensure none of the "right"
signals will ever come into contact with the "wrong" device.
E.g., a multiconductor audio connector wherein "mic" is on a
particular pin, "line in" on two others and "line out on still
others.
Plug in a device that uses all of the above and its one connection.
Plug in separate devices, then separate but compatible connections.
(silly example; but look at DVI connectors and the range of
options they support)
The problem with those is that there's always someone
willing to apply brute force to override the keying.
Can't protect from idiots. I know a guy who plugged a (4p)
power connector into a disk drive "backwards" (I didn't
think that would be possible with *any* amount of effort!)
"Didn't you feel it not fitting?"
The original XT
power supply to MB connectors were like that. The only thing that
kept them from being inserted in the wrong receptacle was some easily
broken keying plastic. I think I killed about 3 motherboards before
the new ATX connectors arrived, which solve the problem. However, it
didn't last, when manufacturers went from 20 pin to 24 pin, using the
same connector and adding another with 4 pins. Now, there was plenty
of opportunity to improperly insert the 20 pin plug in a 24 pin socket
and blowing something up. Yeah, I really like keyed connectors.
That's much like all display advertisements for desktop and laptops.
There are absolutely no cords anywhere in sight. I recall one ad
showing a desktop on the kitchen table, with the requisite smiling
gorgeous blond computing merrily, but with no cables or power plugged
into the easily visible back of the computer. It's almost like
cables, cords, and wires are a necessary evil, not to be shown to
prospective buyers for fear of causing immediate panic or distress.
I think they *do* intimidate many people. Show them a bunch of
wires and they imagine "but how do I know where they'll all go?"
Ok, I'll confess. I'm a slob and have wires everywhere. The mouse
and keyboard go into the back of the desktop. Same with the USB
camera and several USB hard disk drives. I have 4 USB jacks in the
front of my Dell Optiplex 960. Three are filled with cell phone and
smartphone cables, used to sync, replicate, clone, or download data
from the various phones and devices. Most everything else is either
wireless or connected via ethernet.
I leave the front connectors (audio, FW, USB) "free" for transient
things. A thumb drive that I want to plug *just once*, etc.
The first thing that I do when setting up a new machine is glue a
small 4 port powered USB hub onto the back, somewhere (double-sticky
3M "foam"). Then, put all the low speed devices into that:
mouse, keyboard, etc. Leaves the rest of the machine's USB ports
('cept for the one I just used) clear for other devices. If I
need a separate "channel" for a particular high speed device
(video digitizer), I add a 4/5 port card.
My solution to the "two many USB devices" issue is to split peripherals
among different workstations. E.g., scanner and color inkjet don't
need to be attached to machine that I use for CAD -- which needs a
tablet, etc.
All the connectors can be hidden behind doors. The current desktops
by Dell, HP, and Acer have doors to access the connectors. Several of
my customers have removed the doors because they get in the way.
Again, it's like cables and connectors are a customer repellent.
My front connectors hide behind a flimsy door. I keep it closed
lest it snap off! (cuz the connectors aren't used, normally)
Huh? I'm moving cables and connectors around all the time.
Exactly! Just because they *think* (hope) that's the case
(which is how they rationalized putting stuff "out of the
way" on the back) doesn't make it so.
I cheat and use a inspection mirror. Even so, it's a pain to get it
right. Therefore, most of my machines are setup so that I can slide
them forward, lean over the top, and deal with the connector tangle. I
also have photos of the backs of my machines, so I can re-insert the
USB plugs in the same holes. Some drivers don't like it when the USB
port moves.
Mine are under my work tables -- which are pushed up against the wall
(just enough room for cables to sneak up between wall and table).
So, to see behind (with mirror) I have to crawl under table just
to get a mirror in position (or, use binoculars to view a mirror
on a telescopic arm -- I can't read small print at 3 ft in a dimly
lit area!)
Sliding the machines forward means all the cabling is at risk.
Video cables to two monitors, all the USB connections, SCSI
cables, audio cables, network cable, etc.
I.e., I *really* don't like having to crawl around behind machines
UNDER a table just to make sure the DB9 is "correct side up".
Or, that the USB plug is actually lined up with its mate and
not just "upside down".
Only in the late part of the PS/2 era. In the beginning, everything
was either black or beige.
There's a long story here, but I'll save it for another time. There
was some planning, but in the dot com era, almost anything that looked
like a computer was funded and occasionally delivered. Some of these
even sold well.
True, but there's more. Every color has its meaning and effect on the
user. For example, red is suppose to be some form on alarm. Green
means go. Yellow means stop and think about it. See your
neighborhood traffic signal, or industrial designer, for details. The
problem is that these three only apply to the USA. For example, in
China, red means good luck. Trying to find a common ground for color
coding is not a trivial exercise if you plan to ship world wide. For
example, while monitors in the USA came in beige, gray and black,
those sold in Europe came in all kinds of garish colors. These are a
bit over the top, but might give you a clue as the thinking:
<
http://www.empower-yourself-with-color-psychology.com/meaning-of-colors.html>
<
http://www.designbyjoyce.com/color_meanings.html>
You can use *shapes*. E.g., 'O' [sic] and '1'. Or, a consistent
"pull on, push off". Where the information channel is available
to all instead of a select group with a particular skill/sense set.
Product colors are the domain of the industrial designer, who has a
very different criteria for selecting colors.
As for accommodating the needs of the visually impaired, various
federal laws require that access to computing facilities and devices
accommodate such handicaps. However, I don't believe that color
blindness is considered a handicap by any of these laws. I dug into
the ADA web pile, but didn't find anything specific for color
blindness. Since it's not requirement, I suspect color blindness can
be ignored.
<
http://www.ada.gov>
It's not ignored in safety critical applications.
All I could find is a settlement agreement with Wells Fargo bank
agreed to fix the fonts on their web pile so that a color blind user
could set the colors on their computer to improve visibility.
Look at the effort the gummit is going through in order to make
currency more "accessible" to the visually impaired. Look at
the colossal screw ups it's made in the past re: the *unimpaired*
(Susan B Anthony, anybody? :> )