Fax Over Internet Protocol (FoIP)

Fax over Internet Protocol (FoIP) is a fax technology that uses digital packets for Internet transfer. Two key FoIP approaches are store forward and real time. Store forward uses email to transfer data from a source to destination. Real-time is similar to traditional phone line faxing, where IP data packets transfer from source to destination via high-level IP, such as Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). FoIP is also known as IP faxing.

FoIP standards include:

• IP packet data that use routers for decoding.
• Data transmitted via phone, IP gateway or fax modem.
• Configurations, including traditional G3 to G3 fax machine, fax-equipped personal computer (PC) to G3, IP fax machine to G3 and IP fax machine to IP.

FoIP implementation follows a series of sequential steps, as follows:

• Sender transmits signals to receiver.
• Fax session is initiated.
• Receiver responds.
• Sender establishes a connection.
• Faxing begins.
• Each machine exchanges digital control signals that describe page color, size and supported [n1] [n2] data compression, etc. G3 machines use the T.30 protocol to encode digital data as analog and decode analog data as digital.
• Sender scans data and produces a digital bit series represented by black and white converted analog pages.
• Receiver decodes the data, reads each bit and prints data based on bit instructions. The T.38 protocol, used for image data compression and integration (G3), is a real-time FoIP protocol that supports T.30 and converts traditional fax data into an Internet-friendly format.