BCM MX680RD - Front USB3.2 Header: USB3_P56; Serial Port Connectors: COM1, COM2

MX680RD User’s Manual
45
1.9.8 Front USB3.2 Header: USB3_P56
This header provides two USB3.2 Gen 1 port connections (An USB3.2 cable is required).
1.9.9 Serial Port Connectors: COM1, COM2
These headers provides serial connections with serial port COM.
COM1 supports RS232, RS422, RS485 protocols (selected through BIOS).
COM2 supports RS232 protocol.