Re: flexfax: Problem receiving fax with ZyXEL Elite 2864

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

> Nov 27 22:37:19.59: [  726]: --> [2:OK]
> Nov 27 22:37:19.64: [  726]: RECV send MCF (message confirmation)
> Nov 27 22:37:19.64: [  726]: RECV FAX (00000049): from , page 1 in 2:01, INF, 7.7 line/mm, 1-D MR
> Nov 27 22:37:19.64: [  726]: <-- [7:AT+FDR\r]
> Nov 27 22:37:34.49: [  726]: --> [7:+FHS:90]
> Nov 27 22:37:34.51: [  726]: REMOTE HANGUP: Unspecified Phase C error, including too much delay between TCF and +FDR command (code 90)
> 
> What configuration parameter do I have to change in order to reduce delay
> between TCF and +FDR command? I can't seem to find in config(5F) man page.

Why is everything fixable by modifying the configuration?  I wouldn't
expect any configuration pararmeter to control the delay.  If there
were a delay the problem would be in the serial driver or underspecified
hardware.  However, you have sent FDR promptly, so the real question is
why did the modem fail to see it (the timeout appears to be 15 seconds,
so this is hardly a performance problem, unless Hylafax is TOO fast for
the modem).

I do have some evidence that the standard Linux serial driver can lose 
characters on some hardware, although this tends to affect a receive that
overlaps a pause in output.