When adding a device to the Sigfox back end, the PAC code is used as a security precaution. The knowledge of both the Sigfox ID and PAC code goes some way to verify that the device is in the possession of the person adding it to the back end.

Sigfox ID: a 6 to 8 character hexadecimal number. Eg. SIGFOX ID: 21F657

PAC Code: a 16 character hexadecimal number. Eg. PAC: C014626D30040C53

Once a device has been added to a Sigfox customer backend, the PAC code changes. This is a security feature from Sigfox. The code is no longer what is displayed on the label. The owner (which back end it is added to) must obtain the new PAC code from their backend.sigfox.com interface.

When adding a device to the Sigfox back end, both the Sigfox ID and PAC code are needed. If the backend gives an error "Invalid PAC Code", then check the following:

• Double check the Sigfox ID and PAC Code match the label on the device. Check the length of the PAC is 16 characters.
• Has the device been added to a Sigfox back end previously? If so, obtain a new PAC code from the previous back end owner.

A screenshot of the error:

Where to find the new PAC code (Device->Select Device->Information):