On 11/19/2013 12:10 AM, Jeff Liebermann wrote:
> On Mon, 18 Nov 2013 15:33:33 -0700, Don Y <This.is@not.Me> wrote:
>> IMO, better solution is to make it so things won't *fit* in
>> the wrong places! :>
> Right. That usually degenerates into using identical keyed
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
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?"
<shrug> "Yeah, I just pushed harder!"
"Well, congratulations! You now own a toasted disk!"
> 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.
>> Don't know about you but, other than
>> my laptops, I can't *see* anything on the backs of the machines
>> once they are "in place" (under desk, etc).
> 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
>> And, manufacturers don't want to clutter up the front, ACCESSIBLE
>> side of the machine with all those connectors (where they would
>> be easy to access but a cosmetic eyesore).
> 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)
>> So, the rationalization is that "you only do this once" so it
>> can be tedious.
> 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.
>> Is your keyboard mouse plugged into the front USB connectors
>> on your machine? Or, the rear?
>> When you have to unplug either
>> of them (to relocate or untangle), how easy is it to reinsert the
>> plugs? Which side is "up"? Can you "feel" where it should go?
> 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
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".
>> In the PS2 days, could you see the color surrounding each of the two
>> *adjacent* keyboard/mouse connectors?
> Only in the late part of the PS/2 era. In the beginning, everything
> was either black or beige.
>> Like most PC things, they just "happened" -- without much
> 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.
>> You can choose colors that minimize the most common forms of
>> color blindness.
> 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:
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.
>> Just like you can choose "product keys"
>> that use all capital letters (no '1' vs 'l' confusion) and
>> avoid '0' vs. 'O' vs 'Q', '8' vs. 'B', '1' vs 'I', etc.
>> *If* you think about it before *doing* it! :>
> 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.
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? :> )