Res_fax.c: Allowed Rates For V27 Modems

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Hi all,

We are running a fax2email service based on asterisk 1.8.18.0, and we are currently trying out asterisk 1.8.32.2 in our labs. We get the following error when sending faxes out:

[Apr 7 14:34:20] ERROR[16653]: res_fax.c:2121 sendfax_exec: ‘modems’
setting ‘V17,V27,V29’ is incompatible with ‘minrate’ setting 2400

It looks like function check_modem_rate in res_fax.c has been updated and rate 2400 is not allowed for V27 any more. Found the following issue explaining the change:
https://issues.asterisk.org/jira/browse/ASTERISK-23231.

However ITU-T specifications for V27ter (which should supersede the one for V27) specify both 2400 and 4800. We are currently receiving faxes at rate
2400 on our production servers so we can’t upgrade asterisk as is. Does anybody have some insights on this?
Thanks!