Talked to the developer about this issue......It sounds like 30 minutes call drop could be interoperability issue. If theproblem were really there, call-drop interval can be WPA rekey intervalrelated. I guess the AP's wpa rekey interval is set to 30 ...
You need to connect the SPA400 to some network where a DHCP server exists.Then let it get an address and check the DHCP list on the DHCP server.Connect to the SPA400 via Web Page and then adjust the setting to use static IP.