Dial pulse sensor and repeater circuit

A dial pulse sensor and repeater circuit for use in a telephone system including at least one telephone subscriber station connected to a switching center including a battery and switching equipment via a first and a second leads, said subscriber station including dial contacts for causing conductions and interruptions of a DC signal on said first and said second leads, said dial pulse sensor and repeater circuit comprising:

• voltage level sensing means connected between said first and said second leads operated to detect a particular voltage level between said leads in response to said switching center battery applied to said leads by pulses generated by said dial contacts;
• optical coupler means including a light emitting diode and a resistor adjusted to provide a precise voltage and current threshold for operation of said light emitting diode, said optical coupler means connected between said voltage level sensing means and said switching equipment operated in response to said voltage level detected by voltage level sensing means to provide an output signal representative of said dial contact pulses for transmission to said switching equipment;
• and
• circuit timing means connected to said voltage level sensing means and to said first lead for permitting current flow during said interruptions caused by said dial contacts of said subscriber station, said circuit timing means operated during said interruptions of said dial contacts and said circuit timing means non-operated during said conductions of said dial contacts.