Re: [hylafax-users] Config Files and Color Faxing for HylaFax-4.2.2rc5

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

Frank Peters wrote:

> # Some firmwares do not report copy quality correction, although it
> # is present and cannot be disabled.  Thus modem-based CQ must be used.
> Class2CQQueryCmd:	"!(00-02),(00-02)"
> Class2CQCmd:		AT+FCQ=1,0
>  

I believe that I reported this to MultiTech a long, long time ago.  I 
don't know if it was "fixed" or not, but these settings won't hurt anything.

> # Some firmware revisions (i.e. 1.25) report MMR support but corrupt the data.
> # Some firmware revisions (i.e. 1.25 and 1.28) report extended resolution support but
> # have trouble with 300x300 and 400x400 resolutions and corrupt DIS for inch resolutions.
> # Enabling the following lines should work around these things.
> # Compare this against the modem's AT+FCC=? response.
> # Class2DCCQueryCmd:	"!(03),(00-05),(00-02),(00-02),(00-01),(00-01),(00),(00-07)"
> # ModemAnswerCmd:	AT+FCC=03,,,,1,,,,0;A
> # ModemDialCmd:		AT+FCC=03,,,,1,,,,0;DT%s
>  

These are commented-out (so they're just comments, by default, unless 
you uncomment them), and I am quite sure that the problems were fixed by 
MultiTech.

> Class2BUGCmd:		AT+FBU=0	# early firmware is buggy
>  

This was fixed, so you could comment-out this line if you really 
wanted.  Doing that would increase the amount of data communicated 
between the modem and HylaFAX (as it enables HDLC tracing).

> I have updated my modem, the 5634ZPX, with firmware version 1.32k,
> released just a few months ago, and I am wondering if these issues
> still apply.  That is, should the config.<device> file for this modem
> still include these work arounds?
>  

The prototype still needs them as it is, however, you don't need any of 
them, most likely.  That said, however, the defaults are not going to 
hurt or hinder the performance for you, either.

> I don't ordinarily send high resolution faxes, but if the need should
> ever arise it would be good to be prepared.
>  

MultiTech fixed the problem by simply disabling support for those 
resolutions in their firmware.  So if you're going to want ultrafine and 
hyperfine resolution support, then you should use Class 1 or Class 1.0.  
In fact, you'll probably be better-off using Class 1.0 anyway.

> Also, I noticed that HylaFax-4.2.2 now has color and grayscale JPEG
> capabilities (at least in class 1.0).  How exactly is this to be utilized?
> I've noticed no other commands or options that would be associated
> with the sending of JPEG images.
>  

HylaFAX 4.2.2 has the capability (only in Class 1/1.0) to receive color 
and grayscale JPEG faxes (although I've not tested grayscale, as I've 
not found a sender that would ever use it).  Getting that enabled 
requires some work, however.  After the 4.2.2 release I'll be posting a 
message to this forum discussing JPEG and JBIG faxing.  But for those 
who just cannot wait:

 http://bugs.hylafax.org/bugzilla/show_bug.cgi?id=224

I'll probably add a section in the website HOWTO for this, also.  
Essentially, JPEG support requires patching libjpeg and libtiff and 
perhaps rebuilding HylaFAX.  Since the libjpeg development is so slow 
this requirement doesn't appear likely to change very soon, either.

Adding color fax support for Class 2.0/2.1 will require a fair amount of 
coding development... and I didn't anticipate doing that (if ever) until 
HylaFAX were capable of *sending* color faxes (in Class 1).  And, I 
don't have any anticipated time-frame on getting color fax sending 
going, either, since I really don't have any customers wanting/needing it.

Color faxes are extremely rare in the wild.  In fact, most people I have 
talked to about it say, "I didn't know that there was such a thing as a 
color fax."  Even those with color-fax machines (typically HP, Brother, 
and Lexmark) have probably never used that feature.

> Again, I don't have a pressing need to send color images, but I
> do like to keep abreast of the latest changes.
>
> Color profiles seem to be necessary in color fax transmission/reception.
> This is what is indicated on the LittleCMS, an Open Source color
> management tool, web site (http://www.littlecms.com).  How are these
> color profiles to be implemented in HylaFax-4.2.2?

Yes, the colorspace for color faxes is uniquely different from any other 
colorspace used for any other purpose.  The specification came about 
back in the early-days of JPEG popularity, and the CCITT/ITU was a bit 
slow and ultimately nobody really followed the idea after it was done.  
So thus we have a situation where faxing uses a colorspace that is 
unique for faxing and a colorspace that nobody else uses.  So most JPEG 
viewers/decoders are not going to be able to accurately view the 
color-fax TIFFs as received by HylaFAX... they'll have to be converted 
(i.e. to PDF) and undergo a colorspace conversion in the process.

There is such a thing as color JBIG faxes (lossless, as opposed to lossy 
JPEG), and they use the same muddled colorspace as JPEG color faxes.  
However, I've not found a machine in the wild (well, any machine for 
that matter) that supports color JBIG faxing.

Lee.


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