Asus M4A78-EM/1394 - Manual (Page 38)

8. USB connectors (10-1 pin USB78, USB910, USB1112)
These connectors are for USB 2.0 ports. Connect the USB module cable to any of
these connectors, then install the module to a slot opening at the back of the system
chassis. These USB connectors comply with USB 2.0 specification that supports up to
480Mbps connection speed.
Never connect a 1394 cable to the USB connectors. Doing so will damage the
motherboard!
The USB 2.0 module is purchased separately.
9. Optical drive audio connector (4-pin CD)
This connector allows you to receive stereo audio input from sound sources such as a
CD-ROM, TV tuner, or MPEG card.
Chapter 1: Product introduction 1-26