Don't get mini/micro usb cables from a grab-bag or a bin. Get them from the manufacturer of your equipment! Pay the extra money if you have to. I will tell you why soon.
There are 2 different size small ends of mini-USB cables: a micro-USB and a mini-USB. And there are different wirings in addition to that. There also seem to be no standards on mini-USB cables: wiring or content. You will see why I said this later. As for USB connectors, there are:
- Micro-A plugs [4 or 5-pin?]
- Micro-AB receptacles [4 or 5-pin?]
- Micro-B plugs [4 or 5-pin?]
- Micro-B receptacles [4 or 5-pin?]
- Standard-A receptacle to Micro-A plug adapter [don't think this is a jack - we are not concerned with this] [4 or 5-pin?]
- Mini-A plugs [4 or 5-pin?]
- Mini-AB receptacles [4 or 5-pin?]
- Mini-B plugs [4 or 5-pin?]
- Mini-B receptacles [4 or 5-pin?]
- Standard-A receptacle to Mini-A plug adapter [don't think this is a jack - we are not concerned with this] [4 or 5-pin?]
- Micro B plug [8-pin] - very popular on midrange DSLRs, including pins for USB, video output, and often a remote shutter release. not sure if this thing is standardized or not according to wikipedia.
- Micro B(A?) receptacle (8-pin) I think I have one for my DSLR. The wikipedia photo looks like exposed pins - the pins on mine are sunk down in plastic troughs. like a receptacle.
- Slim USB "flat" connectors. no metal jacket. standards violation.
Fire hazard: plugging a micro-USB (loose-fit) cable into a mini-USB equipment can destroy your equipment. (And what about your port? those are expensive!) This can be caused by a number of factors, not the least of which is the fact that the pins are possibly spaced differently due to a different number of pins, and one pin could have been contacting the shield or shorting out the shield and a pin. Don't know for sure. see Occurrance #1.
I have micro plugs with 8 pins, 4 pins and mini plugs with 5 pins. I am sure you can get different varieties these days... Everybody seems to have their own standard.
By the way... I think things like a camera can also ab-use the usb connection in various ways, for example to output a TV [or AV] or similar signal via some sort of adapter but still through the same pins. Those probably differ a lot between cams, so it is still good to be cautious about adapters :-). [hint-the wiring pinout is really different!] I have seen a few of these. If you have equipment that uses USB-AV cables, this is one of those scenarios where you could pop something on your equipment by using a cable from a grab-bin or pick-at-random, because one of the normal USB pins is +5V@500mA, and that would be crashing down against one of the equipment's AV-out or possible a DATA signal, depending on how it is wired.
Occurrance #1: My friend had a digital camera, and he bought a micro-USB cable for it from a local computer store from a grab-bin. it was a loose-fit micro-USB and his camera was a mini-USB. his camera now smells of burnt circuitry. If I remember right I think he said it sparked and went "pop" - can't remember for sure but I think he said it smoked too.
Occurrance #2: I tried a mini-USB cable of mine on a piece of equipment that didn't belong to it but happened to fit. Equipment wouldn't work. plugged the right cable in and voila! it worked! this proved to me that the wiring was different between mfr of cables of the same size. After this I started to label my cables. My DMM's probes are too big to fit in the mini-USB end to test the wiring to find a pinout, so I couldn't use that idea.
If you need a replacement cable, contact the manufacturer of the product and request a replacement part for your make & model number. a little research may save you a lot of money in replacement equipment costs or headache. For example, if you have a Canon camera, go to Canon.com web site and look for either "Customer Service", "Support|Parts/Replacement Parts", or "Support|Get Service" or by whatever means you can find. for instance, on the Canon site, look here for Support|Service. you will not be able to find another proper cable from a store - that is not the way companies do business. they package a whole product and sell it, they do not sell parts like this in stores. There are online stores that carry digital camera cables for model of your digital camera. Try these online stores: showmecables.com, dcables.net, superwarehouse.com.
A good idea: wrap each micro/mini-USB cable you have with masking tape in the middle in a way so you can write easily on it - with about 2 inches sticking out on either side of the cable. center it up, and fold the two sides together to make a flag-like label. Trim the gooey parts of the end off with scsissors. Write on both sides what this cable goes to with a fine Sharpie or a ball point pen. For instance, "White Card Reader", "Minolta D20 Cam", "Red Irocks USB hub", "Black 7-port USB Hub", "Disney-cam". Masking tape lasts for quite a while. if you really want to go all out and get a tool for this, get a cable label printer.
Less expensive label printers like the Dymo handheld model (plastic labels) work for a while but because of the springiness of the plastic they begin to undo themselves after some time. you can use them, but be prepared to press them together once in a while, and make sure your put in about 7 or 8 spaces between the repeated words. Ahh! you can wrap them with clear scotch tape - it doesn't break easy!