GAO's Digital Network Echo Canceller (ITU-T G.168) software module is intended for use in the 4-wire portion of a circuit and is used for reducing the echo by digitally subtracting an estimated echo from the circuit echo. GAO's G.168 echo cancellation software has the following fundamental requirements:

• Rapid convergence
• Low returned echo level during single talk
• Low divergence during double talk
• Assured double talk detection
• Proper operation during facsimile and low speed (9.6 kbit/s) voice-band data transmissions