If you want to link more than 2 openSPOTs together in a private network, then you can use our open source SharkRF IP Connector Protocol server (https://github.com/sharkrf/srf-ip-conn-srv)
If you only want to link 2 openSPOTs together in a private network, then you can set up one openSPOT as a SharkRF IP Connector Protocol server and one as a client. Make sure you've set up port forwarding correctly on the router on the server side.
If you don't care about private networks then you can connect to BrandMeister for example with all openSPOTs. Send all calls to the same talkgroup and the server will link you together. BrandMeister is a DMR server but the openSPOT will handle transcoding from D-STAR for you.
