Call progress detection circuitry and method

A telephone cell placement system comprising:

• a processor for identifying calls to be placed on a statistical basis;
• a plurality of attendants for handling calls placed by said processor;
• a switching network operable in response to calls identified for establishing a call in connection to called lines in response to said processor;
• and
• a call progress detector connectable via said network to calling ones of said lines for controlling connection through said network to idle ones of said attendants, said detector including:
• means for calculating a first ratio level between a peak instantaneous power level of audio signals on said lines and an average power level of said audio signals, and a second ratio level between said peak instantaneous power level of said audio signals and a maximum power level of said audio signals on said lines to determine transitions from one line state to another.

A system for determining telephone line status comprising:

• means for monitoring audio signals on the line to determine transitions from one line state to another;
• wherein said monitoring means includes means for calculating a first ratio level between a peak instantaneous power level of said audio signals and an average power level of said audio signals, and a second ratio level between said peak instantaneous power level of said audio signals and a maximum power level of said audio signals;
• and
• means for comparing said first and second ratio levels to a set of criteria to determine said telephone line status,

A circuit for determining telephone line status comprising:

• means for monitoring audio signals on said line to determine a transition from one line state to another;
• said monitoring means including means for calculating a first ratio level between a peak instantaneous power level of said audio signals and an average power level of said audio signals, and a second ratio level between said peak instantaneous power level of said audio signals and a maximum power level of said audio signals;
• and
• means for comparing said first and second ratio levels to a set of criteria to determine said telephone line status,

A circuit for determining call progress in a communications system, said circuit comprising:

• means for monitoring call progress audio signals on a telephone line;
• means for recording power levels of said monitored call progress audio signals;
• means for calculating a first ratio level between a peak instantaneous power level of said audio signals and an average power level of said call progress audio signals, and a second ratio level between said peak instantaneous power level of said audio signals and a maximum power level of said call progress audio signals;
• and
• means for determining transitions from one line state to another by evaluating said recorded and calculated power levels of said monitored call progress audio signals.