Hi Joeblasi,
Cloud Connector Edition is a hybrid offering that consists of a set of packaged Virtual Machines (VMs) that implement on-premises PSTN connectivity with Cloud PBX. For example, if you have SFB online, but the users homed on SFB online want to use the PSTN
service in SFB on premise, you could deploy CCE, then users in SFB online could use on premise service.
Based on my research, if you want to CCE connect to free PBX, it’s similar to connect to cloud PBX, please refer to the following article
https://technet.microsoft.com/en-us/library/mt605228.aspx
https://technet.microsoft.com/en-us/library/mt612869.aspx

Regards,
Alice Wang
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