IPC Main Group
H04M 5/00 Manual exchanges
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- TELEPHONIC COMMUNICATION
Scope Notes
Limiting references: Substation equipment in general
8 direct subcodes
Child Classifications
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- H04M 5/02 Constructional details
- H04M 5/04 Arrangements for indicating calls or supervising connections for calling or clearing
- H04M 5/08 using connecting means other than cords
- H04M 5/1 using separate plug for each subscriber
- H04M 5/12 Calling substations, e.g. by ringing
- H04M 5/14 Applications of speech amplifiers
- H04M 5/16 with means for reducing interference; with means for reducing effects due to line faults
- H04M 5/18 Arrangements for signalling the class or number of called or calling line from one exchange to another