2G/3G Alerting time

Good day everyone, can you please inform me in Huawei MsoftX3000 what is the timer responsible to decrease or increase the alerting time ( ringing time)?
i tried T301 CM_CT_CALL_RECEIVED , but when i change it from 45s to 90s it worked , but when increasing it to 120 ,it kept disconnection ringing on 90s