It is targeted for Proposed Standard, but it depends overwhelmingly on
other RFCs and drafts that are in flux.  You need to decide on the order
of doing things.

It depends at least on RFCs 2305, 2532, and 3297, and
draft-ietf-fax-esmtp-conneg-10.txt, which Joel reviewed.  2305 is
currently being revised (draft-ietf-fax-service-v2-05.txt).  2532 is
unassigned but a look at the 2305 replacement draft leads me to suspect
that it will be revised after 2305.  You saw Joel's review.  

What do you want to do with these dependencies?  Personally I would hold
off on this draft until those it depends on so heavily are dealt with.

If you want to go forwardi, other than the dependencies there are no
problems, modulo some nits:

Nits:

  - the canonical headings for the references sections are "Normative
    References" and "Informative References".  This has "References -
    Normative" and "References - Informative", and both are subsections
    under "References".

  - It has the 2026 boilerplate.  That can also be fixed by rfc-editor.

Nits that are insignificant on their own:

  - The first sentence of the introduction starts "The current
    specification defines".  This is ambiguous, as proven by my
    misreading it.  Just make it "This specification defines".