Dell Studio 1558 (Early 2010) - Manual (Page 314)

314
Ports
IEEE 1394 Port
Like the USB, IEEE 1394 is a serial data transfer protocol and supports hot
swapping. While the USB 2.0 technology supports speed only upto 480 Mbps,
the IEEE 1394b supports speed upto 800 Mbps. IEEE 1394 is preferred for
high bandwidth applications such as connecting digital video cameras and
external hard drives.
.
Pin Signal
1 TPB–
2 TPB+
3 TPA–
4 TPA+