DIFF Subgroup
H04M 19/02 providing ringing current or supervisory tones, e.g. dialling tone or busy tone
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Current supply arrangements for telephone systems > providing ringing current or supervisory tones, e.g. dialling tone or busy tone
CPC:
Current supply arrangements for telephone systems (for selecting-equipment H04Q1/28) > providing ringing current or supervisory tones, e.g. dialling tone or busy tone
CPC subdivides this area 3x more granularly than IPC with 2 additional codes.
2 codes are CPC-only extensions.
Child Classifications
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- H04M 19/04 the ringing-current being generated at the substations +5 CPC IPC+CPC Available in IPC and CPC