S03-AX: Yes
Rationale
An isolated direct-serial deployment can use locally agreed syntactically valid AX.25-format labels and NET/ROM routes. asc2ax encodes the label/SSID locally; nr_set_mac_address installs the local node address and nr_add_node accepts a locally supplied route. No public IP allocation, DNS delegation or external domain identifier is required for that private deployment. Address uniqueness must still be coordinated locally. This does not infer lawful use of unassigned callsigns on regulated radio, public-network acceptance or global reachability.
Assessment method
Pinned primary-source inspection and bounded configuration/topology inference; no execution
Source context
Linux v6.12 source; NET/ROM 1.3 manual where indicated
Outstanding qualification
Provision private serial node labels with no reused public identity assumptions, add routes and communicate while all external naming/allocation services are unavailable. Avoid RF transmission; deployment regulations are outside this classification.