Firewire® (IEEE 1394) and USB (Universal Serial Bus) are two separate high-speed bus technologies that allow multiple devices to be connected to a computer. The two technologies are not integrated, meaning it is not possible to connect a USB device to a Firewire® port directly. A Firewire® to USB adapter cable for transferring digital video (DV) is available from at least one manufacturer, but it can be expensive and difficult to find.
Even if you don't have a Firewire® to USB adapter cable, it doesn't mean that your Firewire® devices are useless if you have a USB port, or vice versa. Several companies do provide dual hubs. This type of device has two ports in a single hub, which may be either external or internal; one port is used Firewire® and one for USB, allowing either type of device to function. The combination hub is actually two separate ports combined into a single form factor for convenience; there is no conversion between Firewire® and USB taking place when you use one of these hubs.
Another alternative is simply to add two separate cards, assuming your computer has enough available slots. Firewire® and USB cards are both coming down in price, and adding whichever one is missing should not represent a major expense.
Both Firewire® and USB are efficient, high-speed bus standards. A Firewire® hub can support a data transfer rate of up to either 400Mbps or 800Mbps, depending on the standard, and a single Firewire® port can connect up to 63 devices and deliver a guaranteed rate of speed to each one. Firewire® is often used for devices that require real-time operation such as audio and video systems because of this guarantee, and it is also used frequently in storage area networks.
USB can connect more devices (up to 127), but supports data transfer rates of only up to 12Mbps. It is more often used for standard peripherals, such as mice, modems, and keyboards. The USB 2.0 standard supports speeds of up to 480Mbps, which makes it more competitive with Firewire®. On 17 November 2008, USB 3.0 specifications were released, with a transfer rate 10 times that of USB 2.0; consumer devices that use this standard were expected to be available by 2010.
If you cannot purchase a Firewire® to USB adapter, using a hub allows you to use devices that are compatible with either technology. Both technologies support Plug-and-Play and hot-plugging (hot-swappable).
IEEE 1394 to USB Adapter
USB has enjoyed significantly wider adoption than Firewire. It is significantly more likely for a computer to have USB ports and potentially Thunderbolt ports than it is to have a Firewire port. Thus, the most common use case for an adapter is to connect a Firewire device to a USB port.
Adapters are typically dongles, small devices with a short wire that plugs into the USB port and an integrated Firewire port. Some are designed as Firewire to USB cables. These have the Firewire connector on one end and the USB connector on the other and can connect the device straight to the computer.
This is a very easy way to connect your devices and requires minimal technical knowledge (all you need to be able to do is identify which port is which). If you own a Firewire device, such as a camera, you should consider getting an adapter.
USB Type-C and Thunderbolt
If you have a Firewire to USB adapter that has a USB Type-C connector, keep in mind that some modern computers have non-USB ports that use the Type-C connector. Thunderbolt is the most common of these. However, sometimes DisplayPort uses the Type-C connector. Depending on the port and the adapter, plugging into Thunderbolt may not work. If you are unsure, make sure you are plugging into a USB port, not a Thunderbolt one (often marked with a small thunder icon).
USB to Firewire Converter
It is much less common to use a USB to Firewire converter. This is simply because most computers have more USB ports than they have Firewire ports (if they have any of the latter). Therefore, being in a situation of needing a USB port but only having a Firewire port is unlikely.
Nonetheless, this may happen. In some cases, people like to connect USB hubs to Firewire ports. While the Firewire standard cannot handle as many devices as USB (up to 63 versus up to 127), this is typically not a major limiting factor for most use cases. Plus, if you have an unused Firewire port, this can be a great way to put it to good use.
Like the Firewire to USB adapters, adapters for this are usually dongles or full wires. Either can work for your needs, although dongles are significantly more common.
Should You Buy an Adapter?
Using an adapter is typically the simplest way and least expensive way to deal with connecting a Firewire device to a USB port or vice versa. However, it isn’t without drawbacks. For example, if you connect a Firewire device to a USB port using an adapter, you will be limited to the data transfer rate of the port (up to 12Mbps USB 1, up to 480Mbps for USB 2 and up to 20 Gbps for USB 3). So, unless you are using a USB 3.0 or higher port, you may not get the full data transfer capabilities of the device.
Thus, if possible, it is typically best to use devices with compatible ports. If you are using a desktop computer, you can add new ports using an expansion card. A small number of laptops also have ways to expand their input/output ports with new USB, Firewire or other options. However, adding new ports to a laptop is typically more challenging even if it is possible.
As mentioned, another option is to connect a hub that will allow multiple devices to be connected to a single built-in port on your computer. However, it is important to note that all the devices connected to the hub will share the data-transfer bandwidth of the single built-in port. Therefore, it is typically best to connect your hub to a USB 3 port (sometimes marked with blue), Firewire port or other high-speed I/O port.
The Bottom Line
Overall, using an IEEE 1394 to USB adapter is a great option for occasional use or if you do not need the full data transfer speed. Additionally, if you connect a Firewire device to a USB 3 or higher port with an adapter, you can get the full speeds of the device. However, if you are going to be using a Firewire device a lot, consider getting a dedicated port through an expansion card or similar option.
Alternatively, you could consider holding onto an older laptop just for getting video or other data off a Firewire device. Again, this can work for occasional use. For regular use, a dedicated port or a new capture device are the best options.