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Re: [hylafax-users] Transmission problems: info and questions



Ross Boylan wrote:

On Mon, May 29, 2006 at 03:44:59PM -0700, Lee Howard wrote:


Ross Boylan wrote:



...


But as for what you call "protocol attempts" and the man page refers
to  as "attempts to send a particular page", I'm uncertain.



In order to prevent a T.30 incompatibility from racking up 12 phone calls there is this "tries" maximum that involves how many times a call connected with a remote fax device and properly initiated fax protocol, but then broke down on a certain page.


Oh, so the significance of the reference to a "certain page" is that
it means "after the initial setup of the connection."



Yes. But it also has to do with a particular page each time, too. So if in the first call 3 of 5 pages are sent properly but then protocol falls apart on (or after) page 4 is sent, before any confirmation of page 4 is received, then in the next call the fax transmission will start at page 4. If transmission again falls apart at the end of that same page (now the first page being transmitted) then there are two tally marks against that page. By default the job will fail at 3 failures to transmit the same page. If somehow it makes it past that page and then again experiences problems with page 5 then the counter is reset... and so by default each page could, in theory, experience 2 protocol errors each without it causing the job to fail ever. (However, I've never, ever seen that happen.)


(This should almost never happen, by the way, and the fact that it is occcuring is indicative of there being more serious underlying issues.)



From your later question it sounds as if you think this is a software
issue.  Could it be hardware (in the broad sense, including the phone
line)?  Could it be on the other end of the connection?  I have sent
faxes previously to these same people, I think with the same number.
At 47 pages, this is definitely the longest one I've attempted.

Hmm, I have DSL on the same line. Could that be causing trouble?

My results appear to be pretty random, ranging from failures before
any real data are transmitted to failures after 10 pp, and covering a
whole bunch of failure modes (at least to my untrained eye).

Could other seemingly unrelated processes be causing trouble, e.g., if
they used a lot of CPU or caused a lot of swapping? Although the
system has an 800Mhz Athlon, it's definitely sluggish.



All of these things are possibilities. Normally I would approach the problem in this order:


1) check the modem itself, power-cycle it, test it in minicom, etc.
2) check that there are no other processes that could possibly be using the modem
3) check the HylaFAX installation, especially the DSOs, to make sure they're all from the same install. (It's often not good to have some old HylaFAX stuff in /usr/local and new stuff in /usr.)
4) check the line with a different modem


All of this said, since you're using a USR modem I would almost skip to #3 quickly and then on to #4. USR modems have given me way too much grief over the years.

This reminds me: I gave up on fax reception quite awhile ago because I
couldn't get it to work properly (and I have little need for it). I
suppose that is more evidence that something is fishy.



Yeah. Both sending and receiving faxes after an installation is important for testing that installation.


Lee.


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