The security coding of the Infotainment system in higher specced Elites is done by pairing the devices.
For NCDC2013, these devices are:
NCDC2013
GID/CID
CDC3 (bottom half of NCDC2013, but actually is a separate device)
For NCDC2015, these consist of:
NCDC2015
GID/CID
CDC3 (again, bottom half of NCDC2015)
Telematics
All devices must be paired to each other to work. All devices must remain together, you cannot just swap out one of the devices.
To replace a device, all devices need to be unpaired, to put them back into delivery mode. The replacement part also needs to be in delivery mode.
I did an awful lot of work a few years ago to understand the security of these, in order to discover unknown pairing codes (as my NCDR1500/GID/CDC3/Telematics in my MFL MV6 had unknown pairing code, and I wanted to fit a CID), so I probably do know more about these than most. And yes, I did brick a fair few as well.