IPC Subgroup
H04M 1/68 Circuit arrangements for preventing eavesdropping
Introduced: September 1968
Last revised: January 2006
Full Title
Substation equipment, e.g. for use by subscribers > Circuit arrangements for preventing eavesdropping
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- TELEPHONIC COMMUNICATION
1 direct subcode
Child Classifications
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- H04M 1/7 Lock-out or secrecy arrangements in party-line systems