2.4. Configure the modem or the null-modem cable
If a modem is used, configure it to be a dumb modem at the port speed selected in Section 2.3. If the modem accepts Hayes AT commands see Chapter 12 to dumb-down the modem.
Alternatively if a terminal and a null-modem cable are used see Section 11.3, which discusses the pinout of the null modem cable.