This is what I have found and reported to Nexzen customer service
I can reproduce this every time, I have 2 ppc 6700 and here is the scenario. I have the Nexzen paired with the first PPC 6700 and make a test call with my house phone and the nexzen rings with the phone normally. Then I take the second PPC 6700 turn on the Bluetooth and make the PPC discoverable to other devices. Next I call the 2nd PPC, which is not paired with the nexzen at all, after the call I hang up and call the first PPC 6700 and the Nexzen no longer rings with the PPC. There is something in the multiple device programming in the nexzen that is causing the nexzen to not stay paired with the phone when other Bluetooth phones are in the area. I have done some posting on the web and have found other people with this same problem and as contact with other phones ringing is a random concept others cant explain what is happening with their pairing problems. Could you test my findings and see if I have a bad headset or if this is an inherent problem with the Nexzen headset. The nexzen is still the best headset that I have ever owned and if there is a solution to this problem I will be very happy with my decision to purchase this headset. Thanks for your help.
I will follow up here when I have a solution from Nexzen, they have been good about replying promptly to my questions and I have an ongoing service ticket with them.