IPC Main Group
H04M 19/00 Current supply arrangements for telephone systems
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- TELEPHONIC COMMUNICATION
Scope Notes
Limiting references: Current supply for selection equipment
3 direct subcodes
Child Classifications
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- H04M 19/02 providing ringing current or supervisory tones, e.g. dialling tone or busy tone
- H04M 19/06 in which current supply sources at subordinate switching centres are charged from the main exchange
- H04M 19/08 with current supply sources at the substations