Yealink IP Conference Phone CP860/CP920, the CPN10, as a new product designed by Yealink, is a PSTN box to meet the demands in some countries and areas which are still using the public switched telephone network (PSTN). With this PSTN box CPN10, our Yealink CP860/CP920 can both support the conferencing calls based on SIP protocol and PSTN. With one PSTN cable in your meeting room, you can easily connect the PSTN box CPN10 with Yealink professional conference phone CP860/CP920 and start up your local three-way conference. Meanwhile, plus CP860's/CP920's HD audio quality, build-in 3 microphone array, full-duplex technology, acoustic echo cancelling technology as well asits rich call handling features, such as USB call recording, linkage to mobile phones or PCs, you can conveniently enjoy the conferencing call easily with excellent speech quality in your meeting room.