Firewire PCMCIA and Power
There are several different Firewire connections. Some of the more common are 4 pin and 6 pin firewire. The difference between these two connections is that the 6 pin connection has two pins for power, while the 4 pin doesnt. So, you may think to your self “since my firewire device requires power, and I have a 6 pin firewire port on my computer, I’m good to go.” Well, the devil’s in the details of this mess. Not all 6 pin firewire ports supply power to devices.
For example, many PCMCIA Firewire cards have 6 pin ports, yet they have no external power source. Well, it turns out that PCMCIA does not supply enough power on its own to power a Firewire device. In other words, your firewire device will work if it has its own supply of power. If you need to power your 6 pin firewire device, then you will need a port that is built into the Laptop, or you will need a PCMCIA firewire card that plugs into a wall outlet.
Many Firewire hubs have 6 pin ports. But many of these hubs do not power devices. Even some of the hubs that plug into wall outlets do not power devices.
Most PCI cards do supply enough power through Firewire not to cause problems.