On 08/17/2012 06:08 AM, Eric Wieling wrote:> Has anyone experimented with increasing the DAHDI chunk size in improve fax
reliability? If so, did it help, hurt, or not make any difference?
>
I haven't found issues related to the DAHDI chunk size. The main thing
which used to hurt FAXing with Asterisk before Digium launched their own
FAX software was the timing within Asterisk, which they refused to fix
at that time (although independent patches were available). With the
launch of FFA they changed chan_dahdi so on a FAX call the buffering
should change to make the flow of transmitted audio a lot more elastic.
People just tolerate some hiccups in voice calls, but hate latency.
Modem signals must be rigidly timed, but a bit more latency is OK. This
change fixed the main issue affecting all the FAX solutions around. If
that switch in the buffering mode is not happening on your system for
some reason it can badly affect the reliability of FAXes.
Steve