If the issue with pairing S0 to a C-7 hub continues and I want to retire the old C-4, can I use a Nortek stick (from a spare, offline C-4 hub) to do the "No Security" join to the C-7? Will that work with Simplicity Studio?
[I found that my Fibaro FGMS-001 ZW-5 Motion Sensor will only pair with the C-7 using S0.]
If it’s this one
or has a 500 series chip set it should work. (Would assume a 700 series will work also, but doubt that the C4 had a 700 series).
That's the one.
I was under the impression that to do the "No Security" join with the C-7, you had to use a chip/stick that was 500 series. If a 700 series chip/stick would work I have the Silicon Labs UZB-7.
It will work because S2 pairing requires the primary controller, or something to that effect (tagging @erktrek to give the correct reason).
Yep no issues there. I've paired a few Aeotec 7 repeaters that way with my UZB-7.
According to @bcopeland - the S2 authentication keys will not "pass" between secondary and primary controllers but with no security (or S0 - !#@!$@) it would be no prob.
Excellent. Thank you all for the information!
fwiw - I just tried my Nortek stick and could not get it to show up in the PC Controller Sw. I am probably missing a driver or something not sure.. also not familiar enough with the tech to know if I am even in the right place.
Thanks for checking. If I can use the UZB-7, I am set.
I have all of the above mentioned USB ZWave sticks.
Nortec HUSBZB-1 isn't found in PC Controller
SiLabs UZB-3 (500 series) worked on PC Controller but I flashed it with a ZNiffer image and intend to leave it that way.
SiLabs UZB-7 (700 series) works on PC Controller and I have used it to both Add (non-secure) and Replace (non-secure) devices. It's been joined to each of my 3 active ZWave meshes at some point. In other words I can Include-Exclude-Include to move the stick from hub to hub to assist in eliminating ghosts. 90% of it's life has been joined to my C-7.
I have never tried using the Stick to join securely on a C-5, for example. I could get the S0 key and give it to the stick and include devices with S0 but who want's that?? 
Avoiding S0 is my goal. 
I did verify that UZB-7 and a C-7 wouldn't include devices securely (S2) nor would it do a Replace no-secure when the original had S0. Including no-secure had to be done as an Add... for me. in my brief experiments.
Download the Hubitat app
