Whats the difference between Echolink voice and telephone quality voice?
Echolink uses voice compression meaning the quality of the voice is not what is considered “toll quality” but good enough for normal communications. This is why you hear a delay when listening to real-time audio and Echolink audio. The compression is necessary to keep the bandwidth requirements low enough to work with dial-up lines. Normal uncompressed audio requires 64kbps of bandwidth (Telco Standards). Telephone companies also use ADPCM (Adaptive Pulse Code Modulation) schemes to drop the bandwidth requirements even further down to only 32 kbps. Commercial VoIP (Voice over Internet Protocol) applications use about 11kbps of bandwidth.
