Re: flexfax: HylaFAX last page problem: REMOTE HANGUP: Invalid response to MPS (code 53)

["Hans Feringa (HFX)" <hfx@shelob.demon.nl>]

Thanx for the info.

So far I only tested it on receiving fax messages. 
I have an ISDN line, and a Terminal Adapter with 2 POTS ports. I use one
port for an old PABX, and the other port is a dedicated MSNnumber/port
for the modem that is attached to one of my two linux machines.

I tested sending to my Linux machine  with a Teles ISDN card in a
BillyWare 95 machine with the fax software that comes with the Teles card.
(Powerpack). My linux machine has an old fax modem that used to be sold by
the Dutch PTT. I own a little booklet with some of the commands it
supports, but not enough to trouble shoot this problem.

Anyway, I tried with a newer version of this PowerPack software, and tried
again. (because of the suggestion that it was related to an
incompatibility between the two 'modems')
Now I did not see this error anymore, but the resulting (after fax2ps)
document was just black and white, and did not even closely resemble the
document that was sent.

I read thru the config.modem (device = modem), and found something about 
LSB2MSB for sending and receiving, and reversed the order. (to MSB2LSB) 
The config.modem file was created by faxaddmodem (?)
I also had to change some of the AT commands for configuring the modem
before. It had also an entry for TSI (etc/tsi) that I had to remove.

The result is that I now can receive a document that I can read although
with much difficulty, because the conversion from tiff to ps is not really
'clean'. 

These are the messages I get when converting to ps using fax2ps:
Fax3Decode2D: fax00018.tif: Bad code word at scanline 758 (x 1003).
Fax3Decode2D: fax00018.tif: Bad code word at scanline 817 (x 423).
Fax3Decode2D: fax00018.tif: Uncompressed data (not supported) at scanline
1254 (x 1005).
Fax3Decode2D: fax00018.tif: Bad code word at scanline 1939 (x 1060).
Fax3Decode2D: fax00018.tif: Bad code word at scanline 555 (x 345).
Fax3Decode2D: fax00018.tif: Bad code word at scanline 870 (x 755).

The result is that some parts of the received document cannot be read,
because some lines are skipped.

So if this all relates to the modem I am using, I am not going to spend
more time on it to fix it, but I will start looking for a new fax modem.

Since I am using ISDN for all of my communication except faxing, I need
a cheap but good supported modem for HylaFAX. Always open to suggestions.
(a 14k4 modem is more than enough, is it mandatory to have a class 2.0 
modem to be without (future) problems?)

Thanks again for all suggestions and feedback, it brought me closer to
a solution.

I will also check out Andrew Margolis' "Fax Modem Sourcebook"

Hans Feringa

On Mon, 1 Jun 1998, Glenn Burkhardt wrote:

> > Hans Feringa:
> 
> > I tried to find some details of the facsimile protocol, to try and
> > understand the log files better, but the references I found have
> > removed the information since (like www.grayfax.com), or I can 
> > not find them.
> 
> > 1) Where can I find some details about the facsimile protocol
> >    (just enough to 'decode' the log files.)
> > 2) How can I solve this problem.
> 
> Unfortunately, "just enough" tends to be quite a lot.  There's the TIA/EIA-592 spec for Class 2 fax control, and the CCITT T.0 - T.63 recommendations (you really only want the T.30 spec), both available from Global Engineering Documents (800-624-3974).  It's difficult to figure out what's going on without both documents, and even then it's hard.
> 
> The reponse received (Invalid response to MPS) indicates a disagreement amoung
> the fax modems involved about how to proceed.  The MPS signal is described as:
> 
> >From the transmitter to the receiver.
> Multipage signal - To indicate the end of a complete page of facsimile information and to return to the beginning of phase C upon receipt of a confirmation.
> 
> To debug more would require turning up the debug level to get the raw HDLC frames, and, of course, more digging into the spec.
> 
> But unless it's a bad line, the two modems just don't work together.  Does it happen for all locations you try to fax to?  You didn't mention modem type, 
> destination, etc.  
> 
> 
>