IPC Subgroup
H04M 19/02 providing ringing current or supervisory tones, e.g. dialling tone or busy tone
Introduced: September 1968
Last revised: January 2006
Full Title
Current supply arrangements for telephone systems > providing ringing current or supervisory tones, e.g. dialling tone or busy tone
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- TELEPHONIC COMMUNICATION
1 direct subcode
Child Classifications
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- H04M 19/04 the ringing-current being generated at the substations