Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!att!cbnewsi!hrs1
From: hrs1@cbnewsi.att.com (herman.r.silbiger)
Newsgroups: comp.dcom.fax
Subject: Re: Superfine mode
Message-ID: <1991Apr30.133249.13797@cbnewsi.att.com>
Date: 30 Apr 91 13:32:49 GMT
References: <1991Apr28.192301.10631@athena.mit.edu>
Organization: AT&T Bell Laboratories
Lines: 27

In article <1991Apr28.192301.10631@athena.mit.edu>, caserta@athena.mit.edu (Francesco Caserta) writes:
> Many fax machines have now the Superfine transmission option. I remember
> to have read in this newsgroup that this kind of trasmission is actually
> obtained from one of the standard options (std or fine) with a suitable
> shifting.
> 
> Can anyone explain better the situation? In particular, is a superfine
> transmission dependent also of the receiving end? Can two machines, both supporting superfine mode, but of different brand names, perform a
> superfine transmission?
> 
> Thank you very much.
> 
> Francesco Caserta 

The horizontal resolution is specified (at least in Group 3) as number of pels 
along a scan line of specified length.  The scanner has sufficient elements to 
meet that requirements.  The vertical resolution is determined by the number of lines down the page.  To go from basic resolution to fine resolution the stepper
motor which moves the paper is double stepped.  To get superfine it steps 4 
times.   The only way to get a higher horizontal resolution is by having
twice as many elements in the scanner.

As far as your second questions is concerned, the answer is probably not.  Higresolution is a Non-Standard Facility, and is invoked by a manufacturer dependent
code.  A machine from another manufacturer would not know what this code meant,
unless the code has been shared.  This is usually not done, for competetive
reasons.

Herman Silbiger