Re: flexfax: Q: Retrain Negative -- Giving up after 3 tries?

[Robert Colquhoun <rjc@trump.net.au>]

At 11:10 AM 8/11/98 +1000, David Weiss wrote:
>Here is what I know about it:
>
>1. HylaFAX incorrectly encodes fax pages for transmission at 9600. In
>particular, scan line 19 does not conform to the protocol specification:
>it has a zero length run of white picture elements, followed by 187
>fill bits and an end-of-line (measured by a protocol analyser). Scan
>line 19 is the place where the tag line (ie., the string of text at
>the top of every fax page) is spliced to the main page body, so
>perhaps the spice routine is failing (I blame Geri Haliwell for that!).

Ouch!!! - Looks like a encoding error after all, looks like my previous
advice was wrong.  I had thought the some receiving faxes were not
interpretting data correctly. It's hylafaxes fault after all....

>3. There has been some discussion concerning the "correct" response to 
>an RTN, and whether HylaFAX is doing it or not. I'm not sure about
>that. I do know however, that HylaFAX actually responds to the RTN by
>retransmitting the badly encoded page. The receiving device replies with 
>another RTN, and so on, until some error limit is reached. In my case
>that limit is reached after 9 transmissions of the first page, all of
>which I might add, are actually printed by the receiving device and
>appear as successful transmissions.

I might still do what i had previously outlined forcing hylafax to reduce
its requirements on each retrain.

>5. If HylaFAX can be persuaded to transmit at 2400 b/s, rather than
>9600, the encoding error sometimes disappears, and so too, do the RTNs.
>The difficulty here is in persuading HylaFAX to use 2400 for certain
>targets. This is a non-trivial exercise. None of the techniques
>described in the documentation (sendfax -B, destctrls) actually
>functioned (for me) as advertised. Of course, this could be due to my
>ignorance, lack of experience etc, and so I welcome correction.
>However I tried everything I could think of for several days with
>limited success. The _only_ approach that worked, required hacking of
>FaxMachineInfo.c++ to ignore the "info" files, so that the -B option
>to sendfax, actually had an effect. 

You could hand edit the info file to force 2400.  A reducing requirement on
each retrain would presumably do the same thing.


Very much thanks David!! - the protocol analyzer really helped to sort out
the problem.   i might even go buy some Telstra shares ;-)

Now i guess the main problem is to find tag line bug.

PS Hi again Alan!

- Robert