Each version of the FireWire? standard uses a unique number of pins, offers varying transfer speeds, and in some cases also makes use of IDC connector that are shaped differently. These different IDC connector are not always directly compatible with each other, due to the differing pin configurations, sizes, and physical shapes. All of the versions of the FireWire? standard are compatible though, which means it is possible to bridge different FireWire? IDC connector using a variety of adapters and cables.

When FireWire? was first introduced, the IDC connector used four pins. This version of the standard is referred to as FireWire? 400, and it uses the smallest connector out of all the different versions of the standard. A variation on this connector type uses six pins instead, though the additional connections only provide power to external devices, and do not offer additional transfer speed. Both four and six-pin FireWire? IDC connector are referred to as alpha Din41612 connector , and the six-pin version is substantially larger.
The third type of FireWire? connector is typically known as a beta connector. This connector uses nine pins and is physically larger than either the four or six-pin versions xte0juua. Beta IDC connector are used with FireWire? 800 devices, though they are backwards compatible with the correct adapters. When a FireWire? 800 device that is designed to use a beta connector is plugged into a FireWire? 400 device or port, performance and transfer speeds will typically suffer.
