i tried before and there is no internet connection.
do you guys have internet connection?
Not so sure what you mean here. You guys are taking my question to mum_hoe out of context. My question is specific to his special configuration of the ONR.
If you are using normal Huawei ONR configuration by SingTel, then you should be able to get internet access from all 4 ports. And you can connect SingTel TV box to any port. The downside is that your router can only work in AP mode if you want to avoid double NAT.
If you are using ONT (including the case that you have convinced SingTel to configure the Huawei ONR to ONT mode) then only Port 1 is working, you can use SingTel issued AC Plus router. In that case, you can connect Singtel TV box to any port. You can also use a Vlan enabled router from vendors like Asus. In that case, usually the Vlan preset will limit you to be able to connect SingTel TV box to port 4 because of the vlan preset.
Only the Huawei is an ONR. The others like ZTE is configured in ONT mode, even though they may have ONR printed on the housing.