Asus RS700-E6/RS4 - Manual (Page 45)

ASUS RS700-E6/RS4 4-9
4.3 Internal connectors
1. USB connector (4-pin USB7)
This connector is for a A-type internal USB 2.0 device. The USB connector
complies with the USB 2.0 specification that supports up to 480 Mbps
connection speed.
2. Serial port connector (10-1 pin COM2)
This connector is for a serial (COM) port. Connect the serial port module
cable to this connector, then install the module to a slot opening at the back
of the system chassis.
The serial port module is purchased separately.