Re: [hylafax-users] fax log for all black fax

[Lee Howard <faxguy@deanox.com>]

At 11:45 AM 10/16/00 +0300, Dmitry Bely wrote:
>Lee Howard <faxguy@deanox.com> writes:
>
>> The fax recipient of the fax associated with the following log claimed that
>> the faxed page(s) were all black.  I tried the same fax three times, and
>> each time he said the pages were black.  I ended up faxing successfully
>> with a Canon fax machine manually.
>> 
>> Faxing to this person isn't critical to my business, but if this log helps
>> indicate a protocol bug in HylaFAX...
>
>I don't think that's protocol bug.

Why would it work fine with the manual faxing on the Canon and not via
HylaFAX, then?

....
>.. and now we see why. It seems to be that *very* rare case, when RTN means
>sudden line quality degradation and is not related to any protocol
>bugs. Look, we were able to train at 14400 for the first time, but now only 
>training at 7200 has succeeded! Surely something horrible has happened to
>the line in the meantime...

Why would it be consistently bad?  Would the line quality suddenly become
degraded when using HylaFAX or my modem but not when using the manual fax?
I just tried doing the same fax with 'ModemRate: 7200', and the log looks
better (no 4-minute sending), but I can't say whether or not the page is
all black.

>The second page was above 200 Kbytes! No surprise, that it required more
>than 4 minutes to send. But Hylafax itself has nothing to do with it. The
>possible reason is that you are trying to send a grayscale image (not a
>text). Ghostscript may rasterise it with inacceptable quality (looking
>"black" on the other side), and moreover such images are hard to compress
>with T.4 algorithms used for fax transmission. That's why we had so much
>data to send.

Hmm.  I guess I could try sending an ASCII page to them for faxing, but
this is the first time this has happened, and I *always* use the same fax
client which *always* submits the fax in the same TIFF format to HylaFAX.
Meaning, there's never a variance in the type of image that I'm submitting
to HylaFAX (and in this case the content of the image is very typical of my
normal faxes that I send), so why would it differ now?

Thanks,

Lee.



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