Network Working Group Request for Comments: 4161 Category

To allow connectivity between the general switched telephone network facsimile service (GSTN fax) and the e-mail-based Internet Fax service (i-fax), an "Internet Fax Gateway" is required. This document provides guidelines for the optional functionality of Internet Fax Gateways. In this context, an "offramp gateway" provides facsimile data transmission from i-fax to GSTN fax; vice versa, an "onramp gateway" provides data transmission from GSTN fax to i-fax. The recommendations in this document apply to the integrated service including Internet Fax terminals, computers with i-fax software on the Internet, and GSTN fax terminals on the GSTN.