This is called talkoff and there are countermeasures in hardware like Linksys PAP2T/SPA8000. DTMF mode can be set to 'Strict', and Strict Holdoff TIme to 80-90.
After that DTMF will not be triggered by voice, but inband digits muting to convert to RFC2833 will work less reliable, so there can be DTMF artifacts as in our case.

2011/4/30 Boris Kovalenko <boris@tagnet.ru>

Hello!

    My network configuration:
Linksys SPA8000 -> FS -> Cisco 5350 -> PSTN
FS: FreeSWITCH Version 1.0.head (git-1c95ad9 2011-01-20 22-43-50 -0300)
Sometimes, when an user (female) on the Linksys speaks, on the other end
(PSTN) there are "beeps" like DTMF. After googling I found that this
problem is reproducable on some types of hardware where the female
russian voice is incorretly recognized as DTMF. So may I do  some
workaround with FS? For example to disable RFC2833 on Linksys and use
start_dtmf before bridge?

--
С уважением,
  Борис Коваленко
  ЗАО "Тагнет"
  тел. +7 (3435) 230001
  факс +7 (3435) 230005


_______________________________________________
FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org

--
Best regards,

Dmitry Sytchev,
IT Engineer

_______________________________________________
FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org

-- 
Regards,
Boris