For Q1, you should have a door bell switch already. But I am a little concern about the 230V. The interface or relay in GDS3710 has specification of 125V, with max. 60Watt power limitation. Not sure how big is the current in your 230V doorbell, it should be less than 300mA otherwise your doorbell could toast the GDS3710 Alarm_Out1 (or COM1) interface. Also, all the connections in the back board of GDS3710 (that green piece with all the wiring socket) are ALL lower voltage connections while you put 230V high voltage there, if not protected or connected well, could have the risk of short circuits and toast all the PINs affected.
I don’t know where you are but all doorbell in US are binding US Electrical Code and are NOT more than 36V, most are either 24V or 12V.
Because the Chime is not expensive (about 1/10 price of GDS3710), I really suggest you replace that 230V Chime.
You may make it work with GDS3710 if the whole Chime power consumption is less than 60Watt, but you have to pay extra caution and do protection in the wiring/connection. And if short circuit or accident happens, you are on your own. (Because high voltage is NOT recommended to be used in lower voltage electrical appliance as the design is totally different).
For Q2, unless you have static public IP or FQDN domain, it is quite NORMAL you cannot call into your router because of NAT and your router will DROP all the incoming packets and that is exactly how router should do (unless you have IPv6). This is network issue, nothing to do with GDS3710 or ANY device behind your router. If you can configure your router or configure the network in the right way and resolve the domian issue, then the “Call” should be OK to get through. Or like all the Service Provider, all registered to “Cloud” or public Internet, where server will resolve all the NAT issue and will be the proxy to re-link all the parties.
For the Helpdesk, I did not know what happened, but here is the Register Link, please try again:
Thank you for your interest to GDS371xx products.