Asus ESC2000 G2 - Manual (Page 71)

ASUS ESC2000 G2 3-23
9. Power supply SMBus Connector (PSUSMB1)
This connector supplies power for low-speed system management communications.
10. Serial port connectors (10-1 pin COM1/COM2)
These connectors are for the serial (COM) ports. Connect the serial port module cable
to one of these connectors, then install the module to a slot opening at the back of the
system chassis.