IPC Subgroup
H04M 9/08 Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
Introduced: September 1968
Last revised: January 2006
Full Title
Arrangements for interconnection not involving centralised switching > Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- TELEPHONIC COMMUNICATION
1 direct subcode
Child Classifications
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- H04M 9/1 with switching of direction of transmission by voice frequency