CHAPTER 6 Understanding the CME Dial-Plan Analog Voice Port Configuration: • Foreign Exchange Station Ports (FXS): Used to connect analog devices such as analog phones, fax machines or modems to the router. • Foreign Exchange Office Ports (FXO): Used to connect to the PSTN central office (CO) or a Private Branch Exchange (PBX) • Use the Router#show voice port summary Analog Voice Port Configuration: • Configure FXS: Signaling Caller ID information