Telephone signal discriminator

A discriminator device for telephone signals transmitted over a network pair of wires that include at least two coded ring signals with predetermined duration and at least one interruption, comprising:

• A) means for shaping said coded ring signals into square wave-forms further including a first output and a first input, the latter being connected to a network pair of wires;
• B) first timer means having a second input connected to said first output and said first timer means including a second output that is kept at a predetermined state for a first period of time that is slightly larger than the predetermined duration of a coded ring signal;
• C) second timer means having a third input connected to said first output, and said second timer means including a third output that is kept at a predetermined state for a second period of time that starts after said first period of time;
• D) means for detecting the number of interruptions of said coded ring signals over said first period of time and said detecting means including counting means having counting inputs enabled by said second output for said first period of time and said counting means including at least two counting outputs;
• E) at least two first gate means for said counting outputs, respectively, including corresponding first gate means outputs for each of said counting outputs;
• F) at least two second gate means for allowing said first gate means outputs through during said second time period, and further including a second gate means output for each of said first gate means outputs;
• G) at least two switch means for interrupting the connection to a plurality of telephone outlet connections to a pair of wires and said switch means being connected to said second gate means outputs so that all of said switch means are disconnected during said first period of time and only one of said telephone connections is made during said second period of time and corresponding to a predetermined number of interruptions.