Hi, I have two remote offices, each with about 10 extensions. Each office has the 3cx SIP Proxy Manager running on one PC, and the extensions are configured to use the tunnel. From this 3cx web page: http://www.3cx.com/blog/releases/sip-proxy-manager/ - Using the 3CX SIP Proxy Manager - have a couple of questions. 1. Is there a practical limit to the number of extensions at a remote location that would use a single SIP Proxy Manager, running on a single PC at that location? 2. What is the significance of this "Register Expiration" setting?: >6.In the “Register Expiration” enter the re-registration interval – it the inter-site connection is subject to stability issues, it is recommended to reduce this value accordingly. A good reference starting point is 15 minutes. The issue is that we are having random 1-way audio issues with calls in/out of the remote sites. Some days it's perfect, some days it's tolerable (say, 5%), other days it is not tolerable (50%). If you have the answer to the two questions above, that helps me explore that corner. Thanks, Les.