by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses

Full Title

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) > Devices for calling a subscriber (H04M1/66 takes precedence) > Devices which can set up and transmit only one digit at a time > by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses

Child Classifications

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• H04M 1/312
• H04M 1/315 Clutches; Spring assemblies; Speed regulators, e.g. centrifugal brakes (H04M1/32 – H04M1/40 take precedence)
• H04M 1/32 Locking setting devices during transmission to prevent interference by user
• H04M 1/34 Lost-motion or other arrangements for ensuring a pause between successive digit transmissions
• H04M 1/38 Pulses transmitted by a movement variably limited by the setting of a stop
• H04M 1/40 wherein the setting-operation short-circuits or open-circuits the transmitting mechanism during a variable part of a cycle