If I have two sites (main & remote - within same city), both with an UC520 at each site, can I utilize the SIP trunks at the main site for both inbound and outbound calls for the remote site? In another words, say I have 2 DIDs. I'd like to assign one DID to ring at the main site and second DID to ring at the remote site. Is this possible with custom dial-peers and translation profiles?
IPsec VPN will be established between the two sites. I will provide both sites with POTS as a backup incase of SIP or VPN failure.
Are there any sample configs I can refer to?
Yup, you can do that. You are just going to have a dial-peer which points from the remote CME to the HQ CME for the PSTN numbers. And conversely, you'll have dial-peers on HW to point the remote site's DIDs back to that device.