Used in combinationwith Yealink IP Conference Phone CP860/CP920, the CPN10, as a new productdesigned by Yealink, is a PSTN box to meet the demands in some countries andareas which are still using the public switched telephone network (PSTN). Withthis PSTN box CPN10, our Yealink CP860/CP920 can both support the conferencing callbased on SIP protocol and PSTN. With one PSTN cable inyour meeting room, you can easily connect the PSTN box CPN10 with Yealink professional conference phone CP860/CP920 and start up your local three-wayconference. Meanwhile, plus CP860's/CP920's HD audio quality, build-in 3 microphonearray, full-duplex technology, acoustic echo cancelling technology as well asits rich call handling features, such as USB call recording, linkage to mobilephones or PCs, you can conveniently enjoy the conferencing call easily withexcellent speech quality in your meeting room.