For the formerly German Federal Post and Telephone Administration (Deutsche Bundespost), a personal computer was primary a high frequency device.
Therefore every PC sold was attached with an mailing card to registrate the device.
3 Likes
This doesn’t seem much different from the FCC A and B classes for computers that was just getting off the ground back then, the difference, perhaps, being the vendors had to go through the classification hoops, vs (perhaps) the end user having to register something.