Axon and SPA3000 on other internet location

[jason2nl]

I have installed the Axon PBX and have 3 soft phones and a SPA3000 on my LAN working.

Is it also possible to have an other SPA3000 somewhere on the internet connected to my private telephone network ?

I want the outsite SPA3000 only to connection with a phone on my private network without a third party.

 

If this possible with Axon, how can do this ?

Do I have to configure NAT in my ADSL internet router ?

If yes, which port ?

 

Thanks in advance.