BIS-6660CUser Manual14COM1, COM2:PinSignal Name1DCD2TXD3RXD4DTR5GND6DSR7RTS8CTS9RI3.3.2 USB Ports(USB12, USB34, USB56)BPC-7940 provides 4x standard double layer USB2.0 ports and one double-layer USB3.0.(USB5 is USB2.0)USB12,USB34, USB56:PinSignal Name