Asus M4A88TD-M - Manual (Page 39)

7. USB connectors (10-1 pin USB78, USB910, USB1112, USB1314)
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.
8. Serial port connector (10-1 pin COM1)
The connector is for a serial (COM) port. Connect the serial port module cable to the
connector, then install the module to a slot opening at the back of the system chassis.
The serial port module is purchased separately.
ASUS M4A88TD-M 1-27