>>It my humble opinion, the problem is not in your hardware. What's happening,
>>the fax machine on the other end sends negative confirmation on the page you
>>just sent (so-called RTN message).
>OK, I'd buy the argument, except this is happening with a fax group of some
>60 fax machines. Of course, I don't actually know if all 60 respond this way
>to my humble TravelPorte, and I don't intend to find out, but the first dozen
I'm sure they all *do* respond with the RTN.
Quote:>or so all respond the same way. Faxing out through my ZyXEL, which is
>Class 2 although I don't know if that's relevant to this particular
>problem, works just fine.
Class 1 even more strong from the point of view of the response messages. Class
2 modems decode responses internally and report them in form +FPTS: n messages.
Class 1 modems simply forward to the host (PC) what they get from the line, and
then software decodes the information. To solve your problem, we need to figure
out *why* does receiving fax machine send back the RTN message.
I know two reasons for that:
1. Poor quality of the received image, and
2. No RTC in the end of page.
You mentioned that all four copies were of excellent quality, so it is not the
case. Then, it may be RTC problem. RTC (Return To Control) is a special sequence
in page data (six or more End-Of-Line in a row). Receiving fax machine, upon
receipt of the RTC, should stop receiving of page data and proceed to the post
page negotiations. In real life, fax machines wait for the transmitter to drop
page carrier, and then go to post-page. They do it regardless of whether they
received RTC, or not - if they detected that page carrier's gone, they exit page
mode and goto post page. However, many of them notice that there was no RTC, and
consider the page bad - they send RTN.
Class 1 fax modems do not parse the data they are sending, so that the software
is responsible to add RTC to the end of page. Class 2 modems may add RTC
themselves. So, the natural question is: did you try your modem with the software
it came with ?