Fax over IP (FoIP) sends and receives faxes through an Internet connection, eliminating the need for costly modems, analog phone lines, and analog telephone adapters (ATA). In a typical Voice over IP (VoIP) installation, the ATA detects an incoming fax signal and converts the analog tones into the T.38 protocol packets read by an IP network. The Lexmark FoIP application uses fax data that is already formatted into the T.38 standard protocol, enabling a multifunction printer (MFP) to send this data directly to an IP private branch exchange (PBX) through a single network connection. Combining the real-time T.38 protocol with either SIP or H.323 (the most common VoIP protocols) provides fast and reliable FoIP performance within a VoIP environment.