This document shows the best practices for how to program a CyberData SIP Paging Adapter or Server, specifically what SIP settings to use on the CallRevu Hosted Phone System.
See the image below to view the SIP configuration, you can get to this section by clicking on SIP in the menu header of the device:
NOTE: Some ISPs like Comcast and AT&T do not like port 5060 and will end up blocking a lot of SIP traffic. The Local SIP Port can be left at the default 5060 if there is no issue with the device maintaining it's registration. However, if the device will lose its registration often, it is suggested to change the Local SIP Port to 5090.