How is a Soekris box managed

From Soekris Info Wiki

How is a Soekris box managed?

The Soekris box is managed over a serial link using another computer's COM port. Soekris box and computer are connected using a null-modem cable. Management is done from within a serial console on the other computer. Many models have one or more extra Ethernet ports for use as management interface after the OS has been installed.