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FireWire 400 and 800: how to choose 4, 6 or 9 pins
FireWire still turns up on MiniDV and HDV camcorders, audio interfaces, external drives and computers from earlier generations. The problem is rarely recognising the name; it is choosing the right cable. The same family covers both FireWire 400 and FireWire 800, with 4, 6 and 9-pin connectors that do not share the same shape or offer exactly the same features.
The right choice depends on the ports on both devices, not on the connector that looks most familiar. Before you buy, look at both ends, count the contacts and check whether either device needs to draw power from the bus. You can browse the range of FireWire cables and adapters while you compare these features.
FireWire 400 and FireWire 800: what is the difference
FireWire is the usual trade name for IEEE 1394. FireWire 400 normally corresponds to IEEE 1394a and reaches a theoretical speed of up to 400 Mb/s. FireWire 800, associated with IEEE 1394b, raises that figure to 800 Mb/s and generally uses a 9-pin connector.
Effective speed is always limited by the slowest link. If you connect a FireWire 400 device to a FireWire 800 port using the appropriate cable, the link will run at FireWire 400 speed. A cable changes the physical arrangement of the connectors, but it does not turn older equipment into FireWire 800 or double its performance.
It is also worth telling FireWire and USB apart. Although both are used to connect peripherals, their signals and protocols are different. A passive adapter with FireWire on one end and USB on the other does not perform the conversion required. To capture video or recover files, the whole path has to be FireWire compatible.
How to identify 4, 6 and 9-pin connectors
Do not go by size alone. Count the visible contacts and compare the outline of the port with the table:
| Connector | Usual standard | How to recognise it | Bus power | Common use |
|---|---|---|---|---|
| 4-pin | FireWire 400 | Small, with a notch or irregular profile | No | MiniDV/HDV camcorders and compact laptops |
| 6-pin | FireWire 400 | Larger, rectangular with one rounded end | Yes | Computers, audio interfaces and external drives |
| 9-pin | FireWire 800 | Rectangular, more compact than the 6-pin one and with distinct contacts | Yes | Macs, professional drives and FireWire 800 interfaces |
4-pin FireWire
The 4-pin connector carries data but not power. It is very common on camcorders, where it is usually labelled DV, i.LINK or IEEE 1394. The camera will have to run on its battery or mains adapter, even if the other end of the cable is a 6-pin one.
6-pin FireWire
The 6-pin connector adds two contacts intended for power. This allows certain drives or interfaces to work without an external supply, provided that both the host port and the device support that mode. A 4 to 6-pin FireWire cable is the typical choice for connecting a 4-pin DV camcorder to a computer or 6-pin FireWire 400 card; the camera still receives no power through its 4-pin connector.
9-pin FireWire
The 9-pin connector is associated with FireWire 800. Besides offering higher speed between compatible devices, it can communicate with FireWire 400 devices using a suitable 9/6 or 9/4 cable. If both devices have a 9-pin port, a 9 to 9-pin FireWire 800 cable keeps the connection native between them.
Decision tree: which FireWire cable you need
Follow this route before choosing:
- Which connector does the first device have? Work out whether it is 4, 6 or 9-pin.
- Which connector does the second one have? Repeat the check without assuming both are the same.
- If they match: choose 4/4 or 6/6 for FireWire 400 and 9/9 for FireWire 800.
- If one is 4-pin and the other 6-pin: use 4/6. You will get data at FireWire 400 speed, with no power at the 4-pin end.
- If one is 9-pin and the other 6 or 4-pin: use 9/6 or 9/4. The link will work at the level the FireWire 400 device allows.
- Does the computer only have USB? Do not buy a passive USB-FireWire cable. You need a compatible interface or a chain of active adapters supported by the computer, the operating system and the device.
Compatibility, power and speed
A cable with different ends is not necessarily an electronic converter. Between FireWire 400 and 800, the standard itself provides for compatibility across generations when the correct cable is used, but speed is negotiated according to the slowest device. The normal result of joining 400 and 800 is a connection at a theoretical maximum of 400 Mb/s.
Power deserves a separate check. The 6 and 9-pin ports can carry power, but that does not guarantee that any computer will deliver the power any given peripheral requires. If a drive comes with an external supply or the manufacturer recommends one, use it. On a 4/6 or 4/9 link, the 4-pin end never receives power from the bus.
With older equipment, it is sensible to switch off camera, computer and peripheral before connecting or disconnecting, especially where powered ports are involved. Insert each connector straight, without forcing it or turning it the wrong way round, and then switch the devices on as their manual indicates.
Common mistakes when choosing or connecting FireWire
- Confusing 4-pin with mini-USB. They can look alike at first glance, but they are not compatible. Look for the DV, i.LINK or 1394 markings.
- Buying based on a single socket. A cable is defined by both of its ends; check the port on the computer, capture card or drive as well.
- Expecting power from 4 pins. That connector only carries data. Use a battery or an external supply.
- Assuming 9 pins always means 800 Mb/s. If the other device is FireWire 400, the whole connection will run at the lower speed.
- Trying to go straight from FireWire to USB. The shape of the cable does not solve the incompatibility between protocols.
- Forcing the connector. Orientation matters and ports on older equipment can be worn. If it does not go in smoothly, stop and identify it again.
- Ignoring the software. For DV capture, a correct physical connection is not enough: the system has to recognise the FireWire controller and the application has to support the camera format.
Quick check before you buy
Take a sharp photo of each port and count the pins. Note the make and model of both devices, check in their manuals whether the port is IEEE 1394a or 1394b, and confirm whether the peripheral needs external power. Finally, choose the exact combination of ends and a length that does not leave the cable taut.
Frequently asked questions about FireWire cables
Can you connect FireWire 400 to FireWire 800?
Yes, if the devices comply with the standard and you use a cable with the appropriate connectors, such as 9/6 or 9/4. The connection will be limited to FireWire 400 speed.
What is the difference between 4 and 6-pin FireWire?
Both usually work with FireWire 400. The 4-pin one transmits data, while the 6-pin one includes two extra contacts for bus power.
Does a 4 to 6-pin cable power the camcorder?
No. The 4-pin end has no power contacts. The camera needs a battery or a mains adapter.
Can I connect a FireWire camcorder to a USB port?
Not with a passive cable. FireWire and USB use different protocols. You need an active solution that is compatible with the hardware, the operating system and the capture software.
Does a 9-pin cable guarantee FireWire 800 speed?
Only when both ports and devices support FireWire 800. If one of them is FireWire 400, the connection will negotiate a lower speed.
What do DV and i.LINK mean on a camcorder?
They are names used for the digital connection based on IEEE 1394, normally with a 4-pin FireWire port. Identify the port on the destination device as well, so you can choose the other end of the cable.