Minimal FAX address format in Internet Mail (RFC2304)
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
Since the very first e-mail to fax gateway objects appeared, a number of different methods to specify a fax address as an e-mail address have been used by implementors. Two major objectives for this were
Network Working Group C. Allocchio
Request for Comments: 2304 GARR-Italy
Category: Standards Track March 1998
Minimal FAX address format in Internet Mail
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1998). All Rights Reserved.
This memo describes a simple method of encoding PSTN addresses of
facsimile devices in the local-part of Internet email addresses.
As with all Internet mail addresses, the left-hand-side (local- part)
of an address generated according to this specification, is not to be
interpreted except by the MTA that is named on the right-hand-side
Since the very first e-mail to fax gateway objects appeared, a number
of different methods to specify a fax address as an e-mail address
have been used by implementors. Two major objectives for this were
- enable an e-mail user to send faxes from his/her e-mail
- enable some kind of "fax over e-mail service" transport, to
reduce the costs of fax transmissions, and use the existing
This memo describes the MINIMAL addressing method and standard
extensions to encode FAX addresses in e-mail addresses, as required
in reference . The opposite problem, i.e. to allow a traditional
numeric-only fax device user to access the e-mail transport service,
is not discussed here.
All implementations supporting this FAX over e-mail address format
MUST support as a minimum the specification described in this
document. The generic complex case of converting the whole PSTN
addressing in e-mail is out of scope in this minimal specification:
there is some work in progress in the field, where also a number of
standard optional extensions are being defined.
In this document the formal definitions are described using ABNF
syntax, as defined into . We will also use some of the "CORE
DEFINITIONS" defined in "APPENDIX A - CORE" of that document. The
exact meaning of the capitalised words
"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", "OPTIONAL"
is defined in reference .
2. Minimal Fax address
The "service-selector" defined in section 2 of reference  for the
fax service is:
service-selector = "FAX"
The minimal addressing for the fax service also requires support for
a "qualif-type1" element (see section 2 of reference ). This
element is an OPTIONAL element of the fax address, but its support,