Is the PortSIP PBX built on Asterisk, FreeSwitch?

No, PortSIP PBX is not based on any open source PBX; instead, it is developed by PortSIP Team and is based on the open source SIP stack reSIProcate. The reSIProcate is a C++ implementation of SIP, ICE, TURN, and related protocols; many companies, including Cisco, Poly, Dialogic, and Logic, created their products based on the reSIProcate.

Because PortSIP PBX was created by our own team, we can break free from constraints, add more modern unified communications features, optimize performance, and provide highly efficient support, which is why our clients trust us.