H04M 2017/22 — IPC vs CPC Diff | Patent Classification Explorer

DIFF Subgroup Additional Only

H04M 2017/22

Full Title

Prepayment telephone systems (using a coded card to authorise calls from a telephone set H04M1/675)

Of 3 combined children, 0 exist in both systems.

3 codes are CPC-only extensions.

Note: 3 CPC extensions are marked as secondary classification only.

This code exists only in CPC.

Diff view requires codes present in both systems.