this speed, the line *must* be within specs. This is also the upper limit for connections through various types of digital carrier systems that use ADPCM or 32K bits per channel instead of standard 64Kbps PCM encoding. Due to lower sampling rate and fewer bits per sample more quantization noise is generated by the analog-to-digital/digital-to-analog conversions in these systems, thus reducing the Signal to Noise Ration (SNR) limiting speed. 19.2Kbps to
