Hello, no you aren't crazy. Both the AUX sync and CambiumSync methods are supported in the PMP450m, with the same pinouts as the PMP450i to uGPS. Very early versions of the PMP450m firmware had limited support for AUX sync. Ensure that you are at 15.2.1 or higher (I recommend 16.0.1 as of this post) and that the other sync parameters are enabled (Auto-sync or Auto-sync+Free run and AUX port power). Also, the cable should not exceed 10m.
If you are using our newer GPS antenna - cnPulse, be sure to read this FSB and the attachment. http://community.cambiumnetworks.com/t5/PMP-Bulletin-Board/cnPulse-Issue-when-used-with-PMP450m-Field-Service-Bulletin/m-p/99921#M5
If that still doesn't work, a quick support case should resolve the issue.
- cnPulse Webinar 12-2018.pdf (1.18 MB)