FireWire, also known as IEEE 1394, is not a cable that is usually found these days. Popularized in the early '90s, it has long been the competing standard of USB, much like Thunderbolt today. Offering much faster speeds, even faster than USB 2.0, FireWire, a connection that you will usually find on external hard drives and older digital cameras.
FireWire 800 vs 400
FireWire is available in two versions and, unlike USB 2.0 and 3.0, they are not compatible with earlier versions. They are not alike, which can be confusing. The old standard, FireWire 400, is a flatter connector with a rounded side, and the faster 800 version looks like a big USB connector.
The naming scheme is accurate because it represents the actual speed of the cable: 400 Mbps against 800 Mbps. For comparison, the USB 2.0 is at 480 Mbps and the USB 3.0 surpasses it completely with 5 Gbps.
Get a dongle
Unfortunately for FireWire, nowadays you will need a FireWire-to-2018 adapter as much as you will need the cable itself. You can find adapters on AmazonJust make sure the type of FireWire is correct because they are not compatible with each other.
You will also want to avoid a USB 2.0 adapter if you want to connect a FireWire 800 connection because it will be much slower. However, if this is the only way to connect it, running at half the speed is not so bad.