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

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

CPC subdivides this area 4x more granularly than IPC with 3 additional codes.

3 codes are CPC-only extensions.

Child Classifications

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H04M 9/082 CPC only CPC only
H04M 9/085 CPC only CPC only
H04M 9/087 CPC only CPC only
H04M 9/10 with switching of direction of transmission by voice frequency IPC+CPC Available in IPC and CPC