Substation equipment, e.g. for use by subscribers

Classification Context

Section:

ELECTRICITY

Class:

ELECTRIC COMMUNICATION TECHNIQUE

Subclass:

TELEPHONIC COMMUNICATION

Child Classifications

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• H04M 1/02 Constructional features of telephone sets
• H04M 1/24 Arrangements for testing
• H04M 1/247 Telephone sets including user guidance or feature selection means facilitating their use
• H04M 1/253 Telephone sets using digital voice transmission
• H04M 1/26 Devices for calling a subscriber
• H04M 1/56 Arrangements for indicating or recording the called number at the calling subscriber's set
• H04M 1/57 Arrangements for indicating or recording the number of the calling subscriber at the called subscriber's set
• H04M 1/58 Anti-side-tone circuits
• H04M 1/6 including speech amplifiers
• H04M 1/64 Automatic arrangements for answering calls; Automatic arrangements for recording messages for absent subscribers; Arrangements for recording conversations
• H04M 1/66 with means for preventing unauthorised or fraudulent calling
• H04M 1/68 Circuit arrangements for preventing eavesdropping
• H04M 1/71 Substation extension arrangements
• H04M 1/72 Mobile telephones; Cordless telephones, i.e. devices for establishing wireless links to base stations without route selection
• H04M 1/738 Interface circuits for coupling substations to external telephone lines
• H04M 1/78 Circuit arrangements in which low-frequency speech signals proceed in one direction on the line, while speech signals proceeding in the other direction on the line are modulated on a high-frequency carrier signal
• H04M 1/8 Telephone line holding circuits
• H04M 1/82 Line monitoring circuits for call progress or status discrimination