Mixed-Excitation Linear Predictive encoding gives better speech quality than CELP at half the data rate. Encoding and decoding together burn up more than 100% of a TMS320C3x digital signal processor at 33MHz -- 64% to encode and 53% to decode. I don't know how it does on a Pentium or an Alpha. If you have the MIPS at both ends, this enables very robust encrypted speech across modem links to the Internet. John Walker's free SpeakFreely software (http://www.fourmilab.ch/speakfree/windows/speak_freely.html; or follow the link from there to the Unix version) is already doing packet replication for high reliability, using the earlier LPC-10 algorithm. (It doesn't implement MELP, though those on fast CPUs could add it.) I noticed an ad in EE Times that said, "MELP: The new Federal Standard for 2400 bps Speech Coding", so I did a web search for it. It reportedly comes from Georgia Tech research. Atlanta Signal Processors has the exclusive license. See http://www.ti.com/sc/docs/dsps/softcoop/voc-13-1.htm. John Gilmore