Ok youse techies ... what are these thingys?

[Thumper]

I have a bazillion USB cables ... for digital cameras, GPS's, accessories, etc. etc. Many have a cylindrical thingy (different sizes, some smaller than others) built into the cable, yet some are just straight wire cables. I don't pay much attention to which cable came with which accessory as there doesn't seem to be a bit of difference in how they perform. For example, I leave one plugged into my laptop and whenever I need to download info or simply charge an accessory, I just plug it into the existing cable, instead of using the cable that came with each device. (Heck, there's even one on the power cord to my laptop.) SHOULD I pay closer attention? They're obviously put there for some reason but I have no clue why. My question is ... what are they and should I worry about interchanging them with other electronic items? Here's what I'm talking about ... one "straight wire" and one with a "thingy" in-line.

usbthingys 001.JPG

[LJ3]

It's a Ferrite choke... it reduces EMI noise and what not.

[FooBang]

For my camera, the cable requires one of these on it for some reason. Can't use a usb with the filter.

[Chicken Dinner]

I think that's the flux capacitator.

[Thumper]

Half my GPS's have 'em and half don't. My digital camera has one. Why would I have to have a "noise filter" on a camera or GPS? If some GPS's have 'em and some don't, what's the diff? (ALL are Garmin Nuvi's) I don't get it.

[BarryBobPosthole]

Because what goes across them little wires is data. Those are essentially just bandpass filters that sucks the RF out of cables and such. They're not just on those little usb cables they're on a lot of shit.

Or maybe they're there for your anal pleasure.

Pick one.

BKB

[Thumper]

Well, I suppose my question is, are they really needed? I notice no difference if I use a cable with or without. To add to the confusion, why is it I have 12 GPS's from the same maker and half have 'em and half don't? The way companies pinch pennies ... I can't understand why they'd make 'em if they aren't really needed ... and why DON'T they put 'em on everything if they ARE necessary?

I know they're on a lot of stuff ... I can understand why they'd be on the power cord to my laptop, the cords to my wireless phone base station, the cord to my DSL transmitter, etc ... but why a frigging camera? Or, as I said ... a GPS? If one GPS needs one ... why not all of 'em?

[BarryBobPosthole]

A GPS is a receiver for one thing. You want to be headed somewhere depending on a GPS track and have RF interference with your signal?

And FYI, that ain't pictures squirting through that cable when your camera is hooked up dufus, its DATA.

BKB

[Thumper]

I suppose my MAIN question is ... why don't ALL data cables have 'em? I think that's where the confusion comes in.

[BarryBobPosthole]

Prolly because some applications they're used for aren't sensitive to RF and don't make any either. Those filters aren't just to prevent interference but to prevent leakage of RF too. The radio station my parents own has a 250' AM antenna right out back of the station and used to they had a big old tube type transmitter with a heterodyne, or klystron tube if you will, about a foot tall in it. There was RF all over the place in that place. Hell, I sure hope exposure to RF doesn't cause cancer because I've been exposed to plenty of it. the power receptacles were hot with RF even. So they had these filters all over the place in there to keep it to a minimum otherwise you'd hear the radio station on the phone lines and anything that was plugged in practically. So I'm real familiar with the concept. Also learnt about it in Uncle Sam's Air Farce.

Maybe the best answer is 'They're there for a friggin reason'.

And on edit, Niner knows about these things, him bein' a hammy and all I'll bet.

BKB

[Niner]

Maybe this will help....

http://computer.howstuffworks.com/question352.htm

Then again, maybe it won't.