Various PC cable limit lengths?

[techfuzz]

I have a client who is interested in showcasing his use of computer technology by creatively mounting various PC hardware on the walls of his office in some sort of artistic arrangement probably by use of plexi or lexan and or other creative schemes. BTW, this hardware WILL be fully functional and operating 24x7. I have built many computers before but I've never had to deal with placing pieces somewhere other than a computer case. My question is, what are the maximum lengths of the various cables in a PC?
ATA/100?
VGA?
Power/PSU?
FDD?

Can someone run down the list for me and tell me what the maximums are and any special caveats I might need to know about? Thanks!

 

[Peter]

IDE cable length is specified as 18 inches maximum. VGA cables carry analog signals, when they get too long the quality suffers. Legacy FDD cables may be surprisingly long. Long power cables introduce a voltage drop you do NOT want to have.

 

[Abzstrak]

U wont have that metal case shielding things from RF either....

What kind of a weirdo is this guy? computer parts are not aesthetically pleasing, they belong in a box.

 

[IaPuP]

I have a motherbaord on my wall.

It's dead, it won't run....

I have seen running computers screwed to the wall. Harddrives must be left very near the motherboard... perhaps you could put a small drive nearby to boot off and have other drives connected via network/firewire/etc at a greater distance.

I've seen power cables.... well I've seen them maybe 4 feet long. I doubt you want to stretch one across the room if that's what you're thinking.... but a few feet of good cabling probably won't hurt it. Shielding might be beneficial, especially since its not being protected from EMI by the metal case.

VGA cables... if they are the HEAVILY sheilded type (the one I have is 2x thicker than the power cable on my system), you might get 15-20 feet or so without too much loss. If you buy the cheap flimsy VGA extension cables from the computer shop down the street, expect to see ghosted and blurry images.

My best recommendation might be to keep the components in the same area. You can make it look good by having a motherboard, PS and its drives all in the same area. Just keep in mind that you're not in a metal case. Operating computer components outside of a metal case may actually not even be legal in some instances since I think FCC tests for emissions and such are conducted assuming the product is encased somehow. I'm sure certain kinds of businesses would be more worried about that than others.

I'm planning on building a system inside a small plexiglass case sometime here, but I haven't gotten around to it yet.

Good luck,
Eric

 

[Moohooya]

For the harddrive, use firewire, or SCSI. LVD SCSI will give you 12 meters (more than 36 feet) and HVD SCS will give you 25 meters (more than 75 feet). Not sure about firewire, but I'm sure you can look that one up. If you use EIDE, you will be stuck to just a few inches. I don't know how many, but Peter could well be correct wit 18".

Video, as IaPuP said. We have a 12-15' extension here at work. I'm sure they are commonly available for presentations and the like.

Power. Well are you talking before or after the PSU? If it is before, as long as you like, within reason. Go down to WallyMart and pick up an extension cord. It will have a chart of length, current, and wire guage. The longer it it the heavier a guage. Smaller numbers represent a heavier guage. You could easily go 100' with a heavy guage WallyMart extension. If you want even longer, you'll need something heavier that might involve a comercial duty entension. Go to Lowes, or Home Depot and you'll be able to get 250'. The heavier guage will minimise the power drop. And remember, chances are the computer you are reading this on has 100' or more of 12 or 14 guage wire between it and the service panel.

If however, you are talking after the powersupply, then you are more limited. I assume you are not as this would involve more work, but if you are I suggest you open up the PS and solder on heavier guage wires. You should be able to go 1 or 2 meters with only heavier wires. Beyond that you'd need even heavier guage wire, and perhaps some additional noise filtering circuitry cloe to the PC.

Keyboard and mouse should be able to be rather long. Again, for presentations people make extensions. If that is not long enough, either go wireless or USB with a USB hub in the middle to act as a repeater.

Audio, just keep stringing up the wire. Talk to RadioShack and they'll sell you a huge spool of heavy duty audio wire and tell you how many feet you can have. I looked into this once and 50' isn't a huge problem if you get shielded audio cable.

 

[techfuzz]

OK yeah this guy I'm doing this work for is a little eccentric. He's an architect and he's very creative in the head. He gets all kinds of strange and crazy ideas. I have to reel him in sometimes when he gets way out there. I do think his idea of exhibiting the technology is a good idea. You have to see the office space he works in to really understand his intentions, but I'm just trying to understand the limitations before I start on this project.

I am a bit confused though, I have seen some IDE cables as long as 36". Maybe these have some kind of restriction on the devices that can be attached? What do you guys think?
36" Cables Link

I figured the length of the power cable from the wall socket to the power supply could be pretty long, but I hadn't thought about the length of cables from the power supply to the motherboard or to the devices. How hard would it be to open a power supply and change the wires to use a bigger gauge? Has anyone tried this before and not ended up frying their motherboard and/or attached devices?

I don't want to use SCSI unless I absolutely have to. I would like to get a motherboard with as much stuff built onto it as possible so I don't have to stick any PCI or AGP cards on it. I just don't think it would like right that way.

Concerning the EMI, how bad is that? Is it bad for humans? Why would the FCC come looking? Gimme some more details please? Does anyone make some plexi or lexan that blocks EMI so that maybe we could encase the motherboard possibly?

 

[Evadman]

the ATA spec on FDD cabes is 18". I have a 24" in this system, and I have seen 36's. The longer they get, the more data corruption you get. Expecialy with the absance of shielding, you would have to stick with 18". Or go SCSI.

For monitor, I have gone over 20 feet. ( 6' cable and a 15' extension ) and at 1024 x 768 I do not expereance any visable signal artifact.

The EMI is to keep radiation out not in. For the most part, computer devices are pretty "clean" but they can be affected from outside.

 

[lasergecko]

Maybe you should just suggest to this guy one of those clear plexiglass computer cases. But agian there will be the EMI issue.

 

[techfuzz]

lasergecko, no he's pretty set on mounting the components at eye level or above on the wall in some kind of arrangement.

This EMI everyone keeps mentioning. What exactly does it do to a computer? Where does EMI come from and what in an everyday business office environment would be a culprit of EMI?

Thanks for all your help thus far guys!

 

[Peter]

EMI refers to unwanted electromagnetic emissions, and their effects on other equipment. Computers are a major SOURCE of EMI at various frequencies (including common radio frequencies!), and need to be shielded properly to comply with your local government rulings. That'll be pretty hard with no box to start with.

If you've ever seen an EMI detection truck poke its antenna up your building, you'll remember the rules

 

[glugglug]

IDE (ATA) = 22 inches, HOWEVER, the maximum distance between the master and slave devices is 6 inches.
SCSI = 10 meters
Power (assume you mean 4-pin connectors) = technically no limit, but I would strongly recommend keeping the power supply at or near the same altitude (height) as the connected devices or you may run into grounding issues.
VGA = no set limit but crappy connectors in extension cords and/or switchboxes will lead to ghosting
floppy (MFM) = dunno, but given the signal freqency of only 125kHz?? I wouldn't be surprised if you could wire it all the way down the block.

 

[dejitaru]

Rather than the crappy wires, connect each pin with 8-gauge leads. The current drop would be negligible. -or perhaps that's illogical

 

[Mark R]

EMI can go 2 ways:

1) it can affect other equipment. e.g. radios - Try listening to an AM radio station, with the radio placed next to an open PC - all you get is static. Even my computer mouse (unshielded and made from plastic) will drown out stations if it gets close to the AM antenna on my stereo.

2) it can affect the computer. A powerful source of EMI, e.g. a cellular phone can affect sensitive electronics - without adequate shielding of the PC, it is possible that you could get crashes or malfunctions, if someone leaves a cell phone close by. I've tested a GSM phone on a modem (unshielded), and it will drop the call if the phone gets too close.

 

[Peter]

Originally posted by: glugglug
IDE (ATA) = 22 inches, HOWEVER, the maximum distance between the master and slave devices is 6 inches.
SCSI = 10 meters
Power (assume you mean 4-pin connectors) = technically no limit, but I would strongly recommend keeping the power supply at or near the same altitude (height) as the connected devices or you may run into grounding issues.
VGA = no set limit but crappy connectors in extension cords and/or switchboxes will lead to ghosting
floppy (MFM) = dunno, but given the signal freqency of only 125kHz?? I wouldn't be surprised if you could wire it all the way down the block.

Nope ... IDE cable limit has been 18" ever since PIO mode 4 was introduced. SCSI cabling is much more complicated - 10 meters for original SCSI, 5 for Fast-SCSI, 3 with U/UW, less (down to 1.5m) if you have many devices, 12 meters with U2W and U160.

Power cables introduce resistance, which, especially with high amperage devices like mainboards, introduces a voltage drop you don't want - mainboards usually stop running right when the input drops below 4.9V and 3.15V respectively..

Floppy is 500 Kbit/s, this takes the longest cables of those discussed.

VGA is an analog output, with digital sync signals on. Long cables just degrade image quality, if they're way too long you lose the sync signals (thus the picture altogether).

regards, Peter

 

[Somecallmetim]

For the IDE cables, are you saying that as long as the cables are shielded like the ones they sell with what looks like shielding, they can go beyond 18"?

 

[Evadman]

Originally posted by: Peter
EMI refers to unwanted electromagnetic emissions, and their effects on other equipment. Computers are a major SOURCE of EMI at various frequencies (including common radio frequencies!), and need to be shielded properly to comply with your local government rulings. That'll be pretty hard with no box to start with.

If you've ever seen an EMI detection truck poke its antenna up your building, you'll remember the rules

I thought it was just to keep EMI out, not in. Thanks for posting that peter, now I know

 

[techfuzz]

Does anyone know about those rounded IDE cables that have the "silver" lining that "looks" like EMI shielding around them? Is that in fact what it is or just a faux hi-tech lining?

techfuzz

 

[Evadman]

Originally posted by: techfuzz
Does anyone know about those rounded IDE cables that have the "silver" lining that "looks" like EMI shielding around them? Is that in fact what it is or just a faux hi-tech lining?

techfuzz

If it is grounded, I don't see how it could hurt.

 

[0roo0roo]

should work, just get round/colored ide cables, i'm sure he'll love em try to use large fans, 90/120mm low rpm(perhaps vantec stealth fans) for cooling if you bother. i don't see lexan shielding much noise. he should know.. noise affects enviroment. he probably doesn't want an annoying work space


get a psu with temperature sensing. outside a case its fan should run slower. that or replace a cheap power supplies fan with a vantec. there also an antec powersupply with blue lit fans