You can download the stand-alone SIP Proxy Manager from here: https://www.3cx.com/downloads/3CXSIPProxyManager8.msi. IMPORTANT: Use the above link with 3CX Phone System version 8.0.9908 or higher.  Use this one for For Version 7 of the 3CX Phone …

Originally posted here:
Using the 3CX SIP Proxy Manager