Method and apparatus for detecting one or more predetermined tones transmitted over a communication network

A gateway comprising:

• a first network interface;
• and
• an apparatus for detecting predetermined tones transmitted, the apparatus comprising:
• an input to receive a signal transmitted over the first network interface;
• a frequency divider to divide the signal into two different components, each component being associated with a different frequency sub band, wherein each frequency sub band is selected to include a predetermined frequency of a predetermined tone;
• a frequency discriminator to determine frequencies of tones in the components;
• and
• a decision logic block to provide a first indication that a first predetermined tone has been detected when a first determined frequency of a first tone in a first component corresponds to a first predetermined frequency of the first tone.

A method comprising:

• receiving, at a gateway configured to couple a first network (PSTN) to a second network, a signal transmitted over the first network;
• selecting at least two frequency sub bands, the selecting further comprising:
• identifying a plurality of predetermined tones to be detected, each tone having a predetermined frequency;
• mapping the predetermined tones onto a frequency spectrum;
• classifying the predetermined tones by when the tones are expected to be received;
• and
• dividing the frequency spectrum into frequency sub bands based on the mapping and the classifying, such that no two tones that are expected to be received at the same time have frequencies in the same frequency sub band;
• dividing the signal into the frequency sub bands to provide at least two components of the signal in different frequency sub bands;
• determining a first frequency of a first tone in a first component;
• and
• providing an indication that a predetermined tone has been detected when the first frequency corresponds to predetermined frequency of the first tone.