No ring data transmission service is a service whereby household electricity, gas and water meters can be read automatically from contracting meter reading centers by calling that household's telephone over normal telephone lines without having the user's telephone ring. Measured data is output by a printer at the meter reading center. It is even possible to use this service to detect natural gas leaks. If a customer picks up the phone while meter readings are being gathered, the system detects the on-hook status of the telephone and immediately halts transmission thus giving customer phone calls priority.

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