U1900 send setup to the carrier though pra trunk .but receive dissconnect，reason is ”unspecified”.
execute config pra huawei on .on 1910 ,call out ,success .
as we can send signlaing and got reply the trunk seems ok ,
from the signlaing the number type of peer side is SDN/telephony numbering plan ,but we are unknow .
so we need to modify the number type .
for pra trunk ,r&d create a command for it :config pra huawei on .
some time the trunk is ok ,but call fail can check if the peer side need a different numbet type ,we can always find it in the signaling .