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I have an external drive that has one of those mini-USB ports on it, so I can plug it in to my MacBook Pro's USB port. I want to plug it into a IEEE 1394 port. Looking for an adapter online, I found dozens of IEEE 1394 Female to USB Male, but couldn't find any USB Female to IEEE 1394 Male. I'll probably just get a IEEE 1394 enclosure for the drive, but I was curious why I found so many of one and not the other? Is there some technical hardware problem preventing USB Female to FireWire Male? There must be at least some consumer demand for it if the reverse is so easy to find.

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up vote 6 down vote accepted

Besides specifying the gender (male or female), you need to properly specify the type/style of USB connector (A or B). Presumably you are looking for a "female Standard A".

I want to plug it into a IEEE 1394 port.

I can think of two possible reasons for the scarcity of a suitable converter or adapter.

  1. Power conversion: USB supplies +5VDC regulated (2.5 Watts max for USB 2.0), whereas FireWire carries 30VDC unregulated (7-8 Watts max). A DC-to-DC converter might be able to work in this situation.

  2. IEEE 1394 is a peer-to-peer interface. USB is a host-to-gadget (master-to-slave) interface. The adapters you can find would put the FireWire device in the USB gadget role and connect to a USB host; this setup is apparently do-able for both ends in some situations. The scenario you have would put the FireWire device in the USB host (master) role; apparently the typical IEEE 1394 device would not know how to assume the role of a USB host.

Even if you found the "adapter" with the connections you are looking for, that would not mean that the external drive would work with the MacBook. Numerous reviews of one FireWire-to-USB adapter complain of "it doesn't work". These are not simple interfaces, that if you swap in the proper connector or cable type, things will work. Rather these are interconnections that involve compatibility of the electrical power, signal interfaces and the data & control protocol layer at both ends.

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Yeah i figured it wasn't as easy as just sticking an adapter on it, that's why I was surprised to see the opposite of what I was looking for. Thanks for clearing it up. – Marty Aug 25 '12 at 0:18
"... I was surprised ..." - That's reassuring; it seemed you expected to find such an adapter. I'm surprised (like you) that these exist and sort of work. I'd guess that in the situations that do work, that there's FireWire awareness in the USB host software. Or else the FireWire device knows how to emulate a USB gadget. Anyway, if there is an active converter module for IEEE 1394 to USB gadget, then it probably costs more than a few dollars. – sawdust Aug 25 '12 at 0:41
Heh yeah, sometimes I like to put common sense aside and just pretend adapters are magic. Life's easier that way ;) – Marty Aug 25 '12 at 1:14

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