Re: flexfax: Retrain Negative errors

[David Woolley <david@djwhome.demon.co.uk>]

This is something of an FAQ.
> 
> I'm having a number of problems with Hylafax jobs failing with retrain
> negative errors, like this one below.

> Feb 24 14:53:42.74: [23658]: SEND send EOP (no more pages or documents)
> Feb 24 14:53:59.85: [23658]: --> [5:ERROR]

Modem says ERROR.

> Feb 24 14:53:59.85: [23658]: SEND recv RTN (retrain negative)

Hylafaxes guesses that remote machine rejected page with RTN.   It might
just be something else that has caused the modem to reject the operation.

> Many of my users are trying to send faxes to remote locations such as
> India, or Pakistan, as well as more technically modern countries, and so
> I strongly suspect that the quality of remote phone lines is responsible

Bad quality lines will cause this problem and it is the responsibility of
the remote machine to request a retransmission in this way; Hylafax
has to take what it is told on trust, i.e. that the received fax was
not of useable quality.  However, there is a patch for Hylafax to make
it retry the transmissions at successively lower speeds.

Also, there is a bug in the coding of the tag line which can cause some
fax machines to think the whole fax is of unacceptable quality.  There
is a patch for this too.