DIFF Subgroup
H04M 1/58 Anti-side-tone circuits
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Substation equipment, e.g. for use by subscribers > Anti-side-tone circuits
CPC:
Substation equipment, e.g. for use by subscribers (subscriber services or facilities provided at exchanges H04M3/00; prepayment telephone coin boxes H04M17/00; current supply arrangements H04M19/08) > Anti-side-tone circuits
Of 1 combined children, 0 exist in both systems.
1 codes are CPC-only extensions.
Child Classifications
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