[hylafax-devel] Re: Hylafax's Goals & Suitable Modems

[Dr. Harald Pollack <Harald.Pollack@Datanews.at>]

On Wed, 17 May 2000 23:40:29 -0400 (EDT), Robert Hardy wrote:

Hello Robert and Dmitry!

>8o/ If this is true in general (instead of only with the USR 33.6K
>voicemodem) then why not indicate this in the documentation to prevent
>others from wasting weeks of banging their head against HylaFAX!?

I think (and have the experience) that there is no real borderline to distinguish between modems 
which will work and modems which will not work.

Mainly it is a problem of (the RIGHT) initialisation (well, ATZ does its job near 100% :-) AND 
the target (receiver) hard/software of one single fax session.

Assume, that a real faxmachine (in opposit to a faxmodem) is normaly a 'constant' factor and 
could be assumed as an optimal target for almost all faxmodem on the market. But EXCLUDE such toy 
like combi sets like (inexpensive) phone/fax/answering machines.


>I've been trying off and on for the last ~2 years to get a reliable
>maintainable server based linux fax solution going.

Almost not possible :-)))

>Even some of the existing commercial products have problems. 

In comparison to commercial fax products, Hylafax IS reliable (but there exist better solutions 
:-)

>One of the first things I read was the FAQ. Going back now, I see: 
>>From FAQ Q002: "HylaFAX supports a wide variety of modems and is designed to
>support any Class 1, Class 2, or Class 2.0 modem without modification to the
>source code."

This statement is true, but with the restriction, to use only ATZ for initialisation (that's the 
big mystery in fax :-)

>We REALLY need to
>split Hylafax's purpose into two sections:

Better try to split the 'target group' into more sections :-)

> 1. Existing purpose: Works with any modem if you spend enough time hacking it.

Do not hack (it's REALLY NOT necessary), simply set up a reliable profile (profile 0 usually :-) 
and store it ONCE (I repeat: ONCE) by AT&W and only use ATZ in future (wipe out all software, 
which do a AT&W also)

> 2. Stability: Works 99% reliably if you use modem X, Y or Z which you can still buy new.

That's the HUGE PROBLEM ('can still buy now'). Actual modems are mainly 'feature pusher', far 
away from being reliable in fax mode!

BEST faxmodems at all are the old one WITHOUT V.34 and V.90 and all these 'marketing gags'.

>Please understand that I'm a bit frustrated at this point.

i can understand you VERY WELL. But frustration is proportional to (length of) feature list of 
modem.

>I'm on my third or fourth modem from a couple of different manufacturers

So be happy, because if the number of modems increases, frustration will increase also ...

>(USR 33.6K External (clearly a bad choice),

Use it in class 1, it works (almost) perfect (but never change to datamode :-)

>Practical Peripherals 28.8K external, USR Sportster 56K internal w/ latest
>roms and others...)

>Given that Hylafax's goal should be stability, IMHO this section 
>should be reorganized into three categories:
>1. Stable class 2/2.0 modems which work nearly flawlessly with HylaFAX

Will maybe NOT exist at all :-)

>2. Hack modems w/ bugs which will work @ 75-90% if you fight with them enough

Fight against yourself and use strictly ATZ :-)))

>   i.e. USR Modems, Practical Peripherals Modems, Class 1 based modems etc.

Class 1 is the simplest one, because all you have to do is written down in ITU-T.30 (the fax 
standard). Assume, you can use ANY class 1 faxmodem you can buy.

>3. Modems which simply don't work -> Winmodems

>After a lot of discussion/reading (and reading between the lines) I gather
>the following:
>
>-There are no fully compliant class 2.0 modems suitable to a multiuser
> server.

With one exception :-)

> (See Zyxel exclusion below.)

This IS the 'exception', believe me :-)

> Surely this can't be true!?

What "can't be true" ?

> I'm hoping there are several of them which are simply not listed yet.

Class 2.0 (like class 2) is not the best choice for sending fax. The timing is to sensible and 
depends on what manufacturer (the developer of firmware) has assumed to be the best choice. In 
class 1, the programmer of faxsoftware can handle all the timings in a way, he wants!

>-Zyxel modems don't support trailing @ symbols and should be excluded for
> high volume environments. See FAQ http://www.hylafax.org/HylaFAQ/Q318.html

Please FIRST VERIFY, than quote. The 'answer' in the above FAQ is simply NOT THE TRUTH.

Send:     ATE0I1<CR>
Receive:  65204<CR><LF>
Receive:  U90E   0224<CR><LF>
Receive:  2000 03 02 09:45<CR><LF>
Receive:  <CR><LF>
Receive:  OK<CR><LF>

Is in fact a Zyxel U90E ...

Send:     ATDT3102@<CR>

Have used the '@' dial modifier (according to user manual)

Receive:  <CR><LF>
Receive:  NO ANSWER<CR><LF>

Responds with 'NO ANSWER' (and not 'NO CARRIER').

>-Class 1 isn't suitable for a server based fax solutions due to strict timing
> requirements. This eliminates about half the modems listed.

Obviously, you have never tried it. class 1 is the one and only choice for reliability.

>-USR modems do not work properly in class 2.0. 

depends on target equipment. For fax modem as receiver, you might be right.

>We have now have either no information on or have eliminated IMHO the most
>common modems out there. This leaves Multitech & Telebit brand modems in the
>FAQ which actually listed as suitable. Both of which seem to be hard to find
>here and cost significantly more than others which are readily available
>here.

I have one 'rule of thumb': "Who is saying fax has also say ZYXEL" and there is also some 
additional rule (but off topic :-) "... and OS/2" ...

>I'd be willing to do a one off re-write of FAQ Q003 or even write a FAQ
>Q00X "Which modems are suitable for building a stable fax server?"

The answer is: "Almost any class 1 modem, a lot of class 2 modems, build before V.34 was 
invented, and a few class 2.0 modems with handsorted firmware"

>Here that list includes modems from: Acer/A-Open, Creative Labs, Diamond
>Multimedia, D-Link, GVC, Jaton, Motorola & of course USRobotics/3Com.
>
>Does anyone have this information already?

Yes, but nobody believes in :-)

Mit herzlichen Gruessen / Yours sincerely

Dr. Harald Pollack

Harald.Pollack@DATAnews.at



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