Telephone status monitor apparatus

A telephone status monitor apparatus for determining the on/hook and off/hook conditions of a telephone connected across tip and ring terminals across which a ringing voltage may be present and superimposed on normal on/hook and off/hook voltages. The ringing voltage typically has an "on" time of two seconds and an "off" time of four seconds. The apparatus in accordance with the invention includes status circuitry operative under microprocessor control to repetitively sample the voltage across the tip and ring terminals on the minute and on the minute plus three seconds, the latter three second interval being intermediate to the two second "off" time and four second "on" time of the ringing voltage. Each sampled voltage is compared with a reference voltage as a result of which an output signal is produced by the status circuitry having either a first value representative of an apparent on/hook condition or a second value representative of an apparent off/hook condition. The values of successive output signals corresponding to the samples on the minute and on the minute plus three seconds are examined by the microprocessor. When a pair of successive output signals have the same value, either the first value or second value, an output condition representative of an on/hook condition or off/hook condition, respectively, is produced by the microprocessor.