need help to install voip afere new router

[wireless]

i have new installation with router
NH20A
Version du logiciel
v1.00.15 build05
Version de l'équipement
R01
the internet work fine and local iptv also
i need to use voip ata-112 for voice ip
the first days i can call any from lan but i can't receive any call from external
the second days in or out don't work
i make firewall off
dmz on the ata

any can help me to work fine


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